Transcript Chapter 15 - mr-ippolito-science
Slide 1
Chemical Bonding
Objectives:
1.
describe the nature of a chemical bond and its relationship to
valence electrons
2.
compare ionic and covalent bonding
3.
use Lewis Dot Diagrams to represent ionic and covalent compounds
4.
describe the relationship between molecular polarity and bond
polarity
5.
explain the nature and effects of metallic bonding, hydrogen
bonding, and van der Waals forces
6.
compare the structure and properties of polar and nonpolar
molecules
7.
compare the four classes of solids: ionic, molecular, metallic, and
network
Created by C. Ippolito
Dec 2006
Chemical Bonding
• Chemical Bond
– force of attraction that holds atoms together to form
compounds
• Types of Bonds
–
–
–
–
Ionic Bond – transfer electrons – electronegativity >1.67
Covalent Bond – share electrons – electronegativity <1.67
Metallic Bond – free moving electrons in “cloud”
Network Bond – extended covalent bonds
Created by C. Ippolito
Dec 2006
Ionic Bonds
• electrons transferred from one element to another
to complete their valence shells
– Cation – positive ion loses electron – metal
– Anion – negative ion gains electron – nonmetal
• Stable Octet
– atoms gain stability by completing their valence shell
– this is done when shell is filled with eight electrons
• Ionic Compound (salt)
– formed from electrovalent attraction of cation for anion
Created by C. Ippolito
Dec 2006
Lewis Dot Diagrams
• used to represent valence shells of atoms
– kernel – nucleus and all inner energy levels
• represented by the element’s symbol
– valence electrons
• represented by dots surrounding the symbol
• determined by the Group or Family in periodic table
Created by C. Ippolito
Dec 2006
Dot Diagrams of Atoms
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14
• Group 18
Created by C. Ippolito
Dec 2006
Dot Diagrams of Ions
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14 – no ion
• Group 18 – no ion
Created by C. Ippolito
Dec 2006
Covalent Bond
• atoms share electrons to complete valence shell
– molecular substance – atoms held together by covalent bonds
• Nonpolar Covalent Bond
– electrons are shared equally – electronegativity <1.3
• Polar Covalent Bond
– electrons are shared unequally
– electronegativity 1.3<<1.67
• Dipole
– molecule has a slightly positive side (δ+)
– molecule has a slightly negative side (δ-)
Created by C. Ippolito
Dec 2006
Nonpolar Covalent Bond
Representations
• Molecular Formula
• Dot Diagram
• Structural Formula
Created by C. Ippolito
Dec 2006
Multiple Covalent Bonds
• Single Bond
– 1 electron pair shared
• Double Bond
– 2 electron pairs shared
• Triple Bond
– 3 electron pairs shared
Created by C. Ippolito
Dec 2006
Hybridization
• rearrangement of electrons within the
valence orbitals during chemical reactions
– sp hybridization in carbon atom
• 1s22s22p2 configuration is changed in bonding
• one 2s electron is “elevated” to “equalize” all 2
orbitals
– 1s22spx1spy1spz1
Created by C. Ippolito
Dec 2006
Resonance
• explains structures that experimentally do
not conform to dot diagrams
– electrons are seen to move from one bond to
another bond and back again
– they “resonate”
Created by C. Ippolito
Dec 2006
VSEPR Modeling
• Valence Shell Electron Pair Repulsion
– used to explain shapes of molecules
– bonded atom’s electron clouds balance forces of
repulsion and attraction
– this “spaces” them apart as far as they possible
can be from each other
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Tetrahedral Shape
– bond angle 109.47o
– CH4
• Trigonal Pyramidal Shape
– bond angle 107o
– NH3
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Trigonal Planar Shape
– bond angle 120o
– SO3
• Bent Shape
– bond angle 105o
– H2O
• Linear Shape
– bond angle 180o
Created by C. Ippolito
Dec 2006
Hydrogen Bonding
• special attraction between dipoles and compounds
with hydrogen
– hydrogen atom with (δ+) slight positive charge forms
weak bond with highly electronegative atoms in other
molecules that have (δ-) slight negative charge
• special properties of water
– ice less dense than water
– high heat of vaporization (cooling property)
• holds DNA molecule halves together allowing replication
Created by C. Ippolito
Dec 2006
Metallic Bond
• metal atoms in solid and liquid state
– “positive ions” in a “sea” of free flowing
electrons
Created by C. Ippolito
Dec 2006
Network Solids
• covalent crystals
– atoms continuously bonded in a definite pattern
– “one giant” molecule
• very hard
• very high melting points
• poor conductors
Created by C. Ippolito
Dec 2006
Ionic Crystals
• ions packed in a regular pattern
– each anion is surrounded by cations
– each cation surrounded by anions
• high melting point
• nonconductive as solid
• conductive as liquid or dissolved
– because “lattice” structure is broken
Created by C. Ippolito
Dec 2006
Slide 2
Chemical Bonding
Objectives:
1.
describe the nature of a chemical bond and its relationship to
valence electrons
2.
compare ionic and covalent bonding
3.
use Lewis Dot Diagrams to represent ionic and covalent compounds
4.
describe the relationship between molecular polarity and bond
polarity
5.
explain the nature and effects of metallic bonding, hydrogen
bonding, and van der Waals forces
6.
compare the structure and properties of polar and nonpolar
molecules
7.
compare the four classes of solids: ionic, molecular, metallic, and
network
Created by C. Ippolito
Dec 2006
Chemical Bonding
• Chemical Bond
– force of attraction that holds atoms together to form
compounds
• Types of Bonds
–
–
–
–
Ionic Bond – transfer electrons – electronegativity >1.67
Covalent Bond – share electrons – electronegativity <1.67
Metallic Bond – free moving electrons in “cloud”
Network Bond – extended covalent bonds
Created by C. Ippolito
Dec 2006
Ionic Bonds
• electrons transferred from one element to another
to complete their valence shells
– Cation – positive ion loses electron – metal
– Anion – negative ion gains electron – nonmetal
• Stable Octet
– atoms gain stability by completing their valence shell
– this is done when shell is filled with eight electrons
• Ionic Compound (salt)
– formed from electrovalent attraction of cation for anion
Created by C. Ippolito
Dec 2006
Lewis Dot Diagrams
• used to represent valence shells of atoms
– kernel – nucleus and all inner energy levels
• represented by the element’s symbol
– valence electrons
• represented by dots surrounding the symbol
• determined by the Group or Family in periodic table
Created by C. Ippolito
Dec 2006
Dot Diagrams of Atoms
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14
• Group 18
Created by C. Ippolito
Dec 2006
Dot Diagrams of Ions
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14 – no ion
• Group 18 – no ion
Created by C. Ippolito
Dec 2006
Covalent Bond
• atoms share electrons to complete valence shell
– molecular substance – atoms held together by covalent bonds
• Nonpolar Covalent Bond
– electrons are shared equally – electronegativity <1.3
• Polar Covalent Bond
– electrons are shared unequally
– electronegativity 1.3<<1.67
• Dipole
– molecule has a slightly positive side (δ+)
– molecule has a slightly negative side (δ-)
Created by C. Ippolito
Dec 2006
Nonpolar Covalent Bond
Representations
• Molecular Formula
• Dot Diagram
• Structural Formula
Created by C. Ippolito
Dec 2006
Multiple Covalent Bonds
• Single Bond
– 1 electron pair shared
• Double Bond
– 2 electron pairs shared
• Triple Bond
– 3 electron pairs shared
Created by C. Ippolito
Dec 2006
Hybridization
• rearrangement of electrons within the
valence orbitals during chemical reactions
– sp hybridization in carbon atom
• 1s22s22p2 configuration is changed in bonding
• one 2s electron is “elevated” to “equalize” all 2
orbitals
– 1s22spx1spy1spz1
Created by C. Ippolito
Dec 2006
Resonance
• explains structures that experimentally do
not conform to dot diagrams
– electrons are seen to move from one bond to
another bond and back again
– they “resonate”
Created by C. Ippolito
Dec 2006
VSEPR Modeling
• Valence Shell Electron Pair Repulsion
– used to explain shapes of molecules
– bonded atom’s electron clouds balance forces of
repulsion and attraction
– this “spaces” them apart as far as they possible
can be from each other
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Tetrahedral Shape
– bond angle 109.47o
– CH4
• Trigonal Pyramidal Shape
– bond angle 107o
– NH3
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Trigonal Planar Shape
– bond angle 120o
– SO3
• Bent Shape
– bond angle 105o
– H2O
• Linear Shape
– bond angle 180o
Created by C. Ippolito
Dec 2006
Hydrogen Bonding
• special attraction between dipoles and compounds
with hydrogen
– hydrogen atom with (δ+) slight positive charge forms
weak bond with highly electronegative atoms in other
molecules that have (δ-) slight negative charge
• special properties of water
– ice less dense than water
– high heat of vaporization (cooling property)
• holds DNA molecule halves together allowing replication
Created by C. Ippolito
Dec 2006
Metallic Bond
• metal atoms in solid and liquid state
– “positive ions” in a “sea” of free flowing
electrons
Created by C. Ippolito
Dec 2006
Network Solids
• covalent crystals
– atoms continuously bonded in a definite pattern
– “one giant” molecule
• very hard
• very high melting points
• poor conductors
Created by C. Ippolito
Dec 2006
Ionic Crystals
• ions packed in a regular pattern
– each anion is surrounded by cations
– each cation surrounded by anions
• high melting point
• nonconductive as solid
• conductive as liquid or dissolved
– because “lattice” structure is broken
Created by C. Ippolito
Dec 2006
Slide 3
Chemical Bonding
Objectives:
1.
describe the nature of a chemical bond and its relationship to
valence electrons
2.
compare ionic and covalent bonding
3.
use Lewis Dot Diagrams to represent ionic and covalent compounds
4.
describe the relationship between molecular polarity and bond
polarity
5.
explain the nature and effects of metallic bonding, hydrogen
bonding, and van der Waals forces
6.
compare the structure and properties of polar and nonpolar
molecules
7.
compare the four classes of solids: ionic, molecular, metallic, and
network
Created by C. Ippolito
Dec 2006
Chemical Bonding
• Chemical Bond
– force of attraction that holds atoms together to form
compounds
• Types of Bonds
–
–
–
–
Ionic Bond – transfer electrons – electronegativity >1.67
Covalent Bond – share electrons – electronegativity <1.67
Metallic Bond – free moving electrons in “cloud”
Network Bond – extended covalent bonds
Created by C. Ippolito
Dec 2006
Ionic Bonds
• electrons transferred from one element to another
to complete their valence shells
– Cation – positive ion loses electron – metal
– Anion – negative ion gains electron – nonmetal
• Stable Octet
– atoms gain stability by completing their valence shell
– this is done when shell is filled with eight electrons
• Ionic Compound (salt)
– formed from electrovalent attraction of cation for anion
Created by C. Ippolito
Dec 2006
Lewis Dot Diagrams
• used to represent valence shells of atoms
– kernel – nucleus and all inner energy levels
• represented by the element’s symbol
– valence electrons
• represented by dots surrounding the symbol
• determined by the Group or Family in periodic table
Created by C. Ippolito
Dec 2006
Dot Diagrams of Atoms
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14
• Group 18
Created by C. Ippolito
Dec 2006
Dot Diagrams of Ions
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14 – no ion
• Group 18 – no ion
Created by C. Ippolito
Dec 2006
Covalent Bond
• atoms share electrons to complete valence shell
– molecular substance – atoms held together by covalent bonds
• Nonpolar Covalent Bond
– electrons are shared equally – electronegativity <1.3
• Polar Covalent Bond
– electrons are shared unequally
– electronegativity 1.3<<1.67
• Dipole
– molecule has a slightly positive side (δ+)
– molecule has a slightly negative side (δ-)
Created by C. Ippolito
Dec 2006
Nonpolar Covalent Bond
Representations
• Molecular Formula
• Dot Diagram
• Structural Formula
Created by C. Ippolito
Dec 2006
Multiple Covalent Bonds
• Single Bond
– 1 electron pair shared
• Double Bond
– 2 electron pairs shared
• Triple Bond
– 3 electron pairs shared
Created by C. Ippolito
Dec 2006
Hybridization
• rearrangement of electrons within the
valence orbitals during chemical reactions
– sp hybridization in carbon atom
• 1s22s22p2 configuration is changed in bonding
• one 2s electron is “elevated” to “equalize” all 2
orbitals
– 1s22spx1spy1spz1
Created by C. Ippolito
Dec 2006
Resonance
• explains structures that experimentally do
not conform to dot diagrams
– electrons are seen to move from one bond to
another bond and back again
– they “resonate”
Created by C. Ippolito
Dec 2006
VSEPR Modeling
• Valence Shell Electron Pair Repulsion
– used to explain shapes of molecules
– bonded atom’s electron clouds balance forces of
repulsion and attraction
– this “spaces” them apart as far as they possible
can be from each other
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Tetrahedral Shape
– bond angle 109.47o
– CH4
• Trigonal Pyramidal Shape
– bond angle 107o
– NH3
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Trigonal Planar Shape
– bond angle 120o
– SO3
• Bent Shape
– bond angle 105o
– H2O
• Linear Shape
– bond angle 180o
Created by C. Ippolito
Dec 2006
Hydrogen Bonding
• special attraction between dipoles and compounds
with hydrogen
– hydrogen atom with (δ+) slight positive charge forms
weak bond with highly electronegative atoms in other
molecules that have (δ-) slight negative charge
• special properties of water
– ice less dense than water
– high heat of vaporization (cooling property)
• holds DNA molecule halves together allowing replication
Created by C. Ippolito
Dec 2006
Metallic Bond
• metal atoms in solid and liquid state
– “positive ions” in a “sea” of free flowing
electrons
Created by C. Ippolito
Dec 2006
Network Solids
• covalent crystals
– atoms continuously bonded in a definite pattern
– “one giant” molecule
• very hard
• very high melting points
• poor conductors
Created by C. Ippolito
Dec 2006
Ionic Crystals
• ions packed in a regular pattern
– each anion is surrounded by cations
– each cation surrounded by anions
• high melting point
• nonconductive as solid
• conductive as liquid or dissolved
– because “lattice” structure is broken
Created by C. Ippolito
Dec 2006
Slide 4
Chemical Bonding
Objectives:
1.
describe the nature of a chemical bond and its relationship to
valence electrons
2.
compare ionic and covalent bonding
3.
use Lewis Dot Diagrams to represent ionic and covalent compounds
4.
describe the relationship between molecular polarity and bond
polarity
5.
explain the nature and effects of metallic bonding, hydrogen
bonding, and van der Waals forces
6.
compare the structure and properties of polar and nonpolar
molecules
7.
compare the four classes of solids: ionic, molecular, metallic, and
network
Created by C. Ippolito
Dec 2006
Chemical Bonding
• Chemical Bond
– force of attraction that holds atoms together to form
compounds
• Types of Bonds
–
–
–
–
Ionic Bond – transfer electrons – electronegativity >1.67
Covalent Bond – share electrons – electronegativity <1.67
Metallic Bond – free moving electrons in “cloud”
Network Bond – extended covalent bonds
Created by C. Ippolito
Dec 2006
Ionic Bonds
• electrons transferred from one element to another
to complete their valence shells
– Cation – positive ion loses electron – metal
– Anion – negative ion gains electron – nonmetal
• Stable Octet
– atoms gain stability by completing their valence shell
– this is done when shell is filled with eight electrons
• Ionic Compound (salt)
– formed from electrovalent attraction of cation for anion
Created by C. Ippolito
Dec 2006
Lewis Dot Diagrams
• used to represent valence shells of atoms
– kernel – nucleus and all inner energy levels
• represented by the element’s symbol
– valence electrons
• represented by dots surrounding the symbol
• determined by the Group or Family in periodic table
Created by C. Ippolito
Dec 2006
Dot Diagrams of Atoms
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14
• Group 18
Created by C. Ippolito
Dec 2006
Dot Diagrams of Ions
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14 – no ion
• Group 18 – no ion
Created by C. Ippolito
Dec 2006
Covalent Bond
• atoms share electrons to complete valence shell
– molecular substance – atoms held together by covalent bonds
• Nonpolar Covalent Bond
– electrons are shared equally – electronegativity <1.3
• Polar Covalent Bond
– electrons are shared unequally
– electronegativity 1.3<<1.67
• Dipole
– molecule has a slightly positive side (δ+)
– molecule has a slightly negative side (δ-)
Created by C. Ippolito
Dec 2006
Nonpolar Covalent Bond
Representations
• Molecular Formula
• Dot Diagram
• Structural Formula
Created by C. Ippolito
Dec 2006
Multiple Covalent Bonds
• Single Bond
– 1 electron pair shared
• Double Bond
– 2 electron pairs shared
• Triple Bond
– 3 electron pairs shared
Created by C. Ippolito
Dec 2006
Hybridization
• rearrangement of electrons within the
valence orbitals during chemical reactions
– sp hybridization in carbon atom
• 1s22s22p2 configuration is changed in bonding
• one 2s electron is “elevated” to “equalize” all 2
orbitals
– 1s22spx1spy1spz1
Created by C. Ippolito
Dec 2006
Resonance
• explains structures that experimentally do
not conform to dot diagrams
– electrons are seen to move from one bond to
another bond and back again
– they “resonate”
Created by C. Ippolito
Dec 2006
VSEPR Modeling
• Valence Shell Electron Pair Repulsion
– used to explain shapes of molecules
– bonded atom’s electron clouds balance forces of
repulsion and attraction
– this “spaces” them apart as far as they possible
can be from each other
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Tetrahedral Shape
– bond angle 109.47o
– CH4
• Trigonal Pyramidal Shape
– bond angle 107o
– NH3
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Trigonal Planar Shape
– bond angle 120o
– SO3
• Bent Shape
– bond angle 105o
– H2O
• Linear Shape
– bond angle 180o
Created by C. Ippolito
Dec 2006
Hydrogen Bonding
• special attraction between dipoles and compounds
with hydrogen
– hydrogen atom with (δ+) slight positive charge forms
weak bond with highly electronegative atoms in other
molecules that have (δ-) slight negative charge
• special properties of water
– ice less dense than water
– high heat of vaporization (cooling property)
• holds DNA molecule halves together allowing replication
Created by C. Ippolito
Dec 2006
Metallic Bond
• metal atoms in solid and liquid state
– “positive ions” in a “sea” of free flowing
electrons
Created by C. Ippolito
Dec 2006
Network Solids
• covalent crystals
– atoms continuously bonded in a definite pattern
– “one giant” molecule
• very hard
• very high melting points
• poor conductors
Created by C. Ippolito
Dec 2006
Ionic Crystals
• ions packed in a regular pattern
– each anion is surrounded by cations
– each cation surrounded by anions
• high melting point
• nonconductive as solid
• conductive as liquid or dissolved
– because “lattice” structure is broken
Created by C. Ippolito
Dec 2006
Slide 5
Chemical Bonding
Objectives:
1.
describe the nature of a chemical bond and its relationship to
valence electrons
2.
compare ionic and covalent bonding
3.
use Lewis Dot Diagrams to represent ionic and covalent compounds
4.
describe the relationship between molecular polarity and bond
polarity
5.
explain the nature and effects of metallic bonding, hydrogen
bonding, and van der Waals forces
6.
compare the structure and properties of polar and nonpolar
molecules
7.
compare the four classes of solids: ionic, molecular, metallic, and
network
Created by C. Ippolito
Dec 2006
Chemical Bonding
• Chemical Bond
– force of attraction that holds atoms together to form
compounds
• Types of Bonds
–
–
–
–
Ionic Bond – transfer electrons – electronegativity >1.67
Covalent Bond – share electrons – electronegativity <1.67
Metallic Bond – free moving electrons in “cloud”
Network Bond – extended covalent bonds
Created by C. Ippolito
Dec 2006
Ionic Bonds
• electrons transferred from one element to another
to complete their valence shells
– Cation – positive ion loses electron – metal
– Anion – negative ion gains electron – nonmetal
• Stable Octet
– atoms gain stability by completing their valence shell
– this is done when shell is filled with eight electrons
• Ionic Compound (salt)
– formed from electrovalent attraction of cation for anion
Created by C. Ippolito
Dec 2006
Lewis Dot Diagrams
• used to represent valence shells of atoms
– kernel – nucleus and all inner energy levels
• represented by the element’s symbol
– valence electrons
• represented by dots surrounding the symbol
• determined by the Group or Family in periodic table
Created by C. Ippolito
Dec 2006
Dot Diagrams of Atoms
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14
• Group 18
Created by C. Ippolito
Dec 2006
Dot Diagrams of Ions
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14 – no ion
• Group 18 – no ion
Created by C. Ippolito
Dec 2006
Covalent Bond
• atoms share electrons to complete valence shell
– molecular substance – atoms held together by covalent bonds
• Nonpolar Covalent Bond
– electrons are shared equally – electronegativity <1.3
• Polar Covalent Bond
– electrons are shared unequally
– electronegativity 1.3<<1.67
• Dipole
– molecule has a slightly positive side (δ+)
– molecule has a slightly negative side (δ-)
Created by C. Ippolito
Dec 2006
Nonpolar Covalent Bond
Representations
• Molecular Formula
• Dot Diagram
• Structural Formula
Created by C. Ippolito
Dec 2006
Multiple Covalent Bonds
• Single Bond
– 1 electron pair shared
• Double Bond
– 2 electron pairs shared
• Triple Bond
– 3 electron pairs shared
Created by C. Ippolito
Dec 2006
Hybridization
• rearrangement of electrons within the
valence orbitals during chemical reactions
– sp hybridization in carbon atom
• 1s22s22p2 configuration is changed in bonding
• one 2s electron is “elevated” to “equalize” all 2
orbitals
– 1s22spx1spy1spz1
Created by C. Ippolito
Dec 2006
Resonance
• explains structures that experimentally do
not conform to dot diagrams
– electrons are seen to move from one bond to
another bond and back again
– they “resonate”
Created by C. Ippolito
Dec 2006
VSEPR Modeling
• Valence Shell Electron Pair Repulsion
– used to explain shapes of molecules
– bonded atom’s electron clouds balance forces of
repulsion and attraction
– this “spaces” them apart as far as they possible
can be from each other
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Tetrahedral Shape
– bond angle 109.47o
– CH4
• Trigonal Pyramidal Shape
– bond angle 107o
– NH3
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Trigonal Planar Shape
– bond angle 120o
– SO3
• Bent Shape
– bond angle 105o
– H2O
• Linear Shape
– bond angle 180o
Created by C. Ippolito
Dec 2006
Hydrogen Bonding
• special attraction between dipoles and compounds
with hydrogen
– hydrogen atom with (δ+) slight positive charge forms
weak bond with highly electronegative atoms in other
molecules that have (δ-) slight negative charge
• special properties of water
– ice less dense than water
– high heat of vaporization (cooling property)
• holds DNA molecule halves together allowing replication
Created by C. Ippolito
Dec 2006
Metallic Bond
• metal atoms in solid and liquid state
– “positive ions” in a “sea” of free flowing
electrons
Created by C. Ippolito
Dec 2006
Network Solids
• covalent crystals
– atoms continuously bonded in a definite pattern
– “one giant” molecule
• very hard
• very high melting points
• poor conductors
Created by C. Ippolito
Dec 2006
Ionic Crystals
• ions packed in a regular pattern
– each anion is surrounded by cations
– each cation surrounded by anions
• high melting point
• nonconductive as solid
• conductive as liquid or dissolved
– because “lattice” structure is broken
Created by C. Ippolito
Dec 2006
Slide 6
Chemical Bonding
Objectives:
1.
describe the nature of a chemical bond and its relationship to
valence electrons
2.
compare ionic and covalent bonding
3.
use Lewis Dot Diagrams to represent ionic and covalent compounds
4.
describe the relationship between molecular polarity and bond
polarity
5.
explain the nature and effects of metallic bonding, hydrogen
bonding, and van der Waals forces
6.
compare the structure and properties of polar and nonpolar
molecules
7.
compare the four classes of solids: ionic, molecular, metallic, and
network
Created by C. Ippolito
Dec 2006
Chemical Bonding
• Chemical Bond
– force of attraction that holds atoms together to form
compounds
• Types of Bonds
–
–
–
–
Ionic Bond – transfer electrons – electronegativity >1.67
Covalent Bond – share electrons – electronegativity <1.67
Metallic Bond – free moving electrons in “cloud”
Network Bond – extended covalent bonds
Created by C. Ippolito
Dec 2006
Ionic Bonds
• electrons transferred from one element to another
to complete their valence shells
– Cation – positive ion loses electron – metal
– Anion – negative ion gains electron – nonmetal
• Stable Octet
– atoms gain stability by completing their valence shell
– this is done when shell is filled with eight electrons
• Ionic Compound (salt)
– formed from electrovalent attraction of cation for anion
Created by C. Ippolito
Dec 2006
Lewis Dot Diagrams
• used to represent valence shells of atoms
– kernel – nucleus and all inner energy levels
• represented by the element’s symbol
– valence electrons
• represented by dots surrounding the symbol
• determined by the Group or Family in periodic table
Created by C. Ippolito
Dec 2006
Dot Diagrams of Atoms
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14
• Group 18
Created by C. Ippolito
Dec 2006
Dot Diagrams of Ions
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14 – no ion
• Group 18 – no ion
Created by C. Ippolito
Dec 2006
Covalent Bond
• atoms share electrons to complete valence shell
– molecular substance – atoms held together by covalent bonds
• Nonpolar Covalent Bond
– electrons are shared equally – electronegativity <1.3
• Polar Covalent Bond
– electrons are shared unequally
– electronegativity 1.3<<1.67
• Dipole
– molecule has a slightly positive side (δ+)
– molecule has a slightly negative side (δ-)
Created by C. Ippolito
Dec 2006
Nonpolar Covalent Bond
Representations
• Molecular Formula
• Dot Diagram
• Structural Formula
Created by C. Ippolito
Dec 2006
Multiple Covalent Bonds
• Single Bond
– 1 electron pair shared
• Double Bond
– 2 electron pairs shared
• Triple Bond
– 3 electron pairs shared
Created by C. Ippolito
Dec 2006
Hybridization
• rearrangement of electrons within the
valence orbitals during chemical reactions
– sp hybridization in carbon atom
• 1s22s22p2 configuration is changed in bonding
• one 2s electron is “elevated” to “equalize” all 2
orbitals
– 1s22spx1spy1spz1
Created by C. Ippolito
Dec 2006
Resonance
• explains structures that experimentally do
not conform to dot diagrams
– electrons are seen to move from one bond to
another bond and back again
– they “resonate”
Created by C. Ippolito
Dec 2006
VSEPR Modeling
• Valence Shell Electron Pair Repulsion
– used to explain shapes of molecules
– bonded atom’s electron clouds balance forces of
repulsion and attraction
– this “spaces” them apart as far as they possible
can be from each other
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Tetrahedral Shape
– bond angle 109.47o
– CH4
• Trigonal Pyramidal Shape
– bond angle 107o
– NH3
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Trigonal Planar Shape
– bond angle 120o
– SO3
• Bent Shape
– bond angle 105o
– H2O
• Linear Shape
– bond angle 180o
Created by C. Ippolito
Dec 2006
Hydrogen Bonding
• special attraction between dipoles and compounds
with hydrogen
– hydrogen atom with (δ+) slight positive charge forms
weak bond with highly electronegative atoms in other
molecules that have (δ-) slight negative charge
• special properties of water
– ice less dense than water
– high heat of vaporization (cooling property)
• holds DNA molecule halves together allowing replication
Created by C. Ippolito
Dec 2006
Metallic Bond
• metal atoms in solid and liquid state
– “positive ions” in a “sea” of free flowing
electrons
Created by C. Ippolito
Dec 2006
Network Solids
• covalent crystals
– atoms continuously bonded in a definite pattern
– “one giant” molecule
• very hard
• very high melting points
• poor conductors
Created by C. Ippolito
Dec 2006
Ionic Crystals
• ions packed in a regular pattern
– each anion is surrounded by cations
– each cation surrounded by anions
• high melting point
• nonconductive as solid
• conductive as liquid or dissolved
– because “lattice” structure is broken
Created by C. Ippolito
Dec 2006
Slide 7
Chemical Bonding
Objectives:
1.
describe the nature of a chemical bond and its relationship to
valence electrons
2.
compare ionic and covalent bonding
3.
use Lewis Dot Diagrams to represent ionic and covalent compounds
4.
describe the relationship between molecular polarity and bond
polarity
5.
explain the nature and effects of metallic bonding, hydrogen
bonding, and van der Waals forces
6.
compare the structure and properties of polar and nonpolar
molecules
7.
compare the four classes of solids: ionic, molecular, metallic, and
network
Created by C. Ippolito
Dec 2006
Chemical Bonding
• Chemical Bond
– force of attraction that holds atoms together to form
compounds
• Types of Bonds
–
–
–
–
Ionic Bond – transfer electrons – electronegativity >1.67
Covalent Bond – share electrons – electronegativity <1.67
Metallic Bond – free moving electrons in “cloud”
Network Bond – extended covalent bonds
Created by C. Ippolito
Dec 2006
Ionic Bonds
• electrons transferred from one element to another
to complete their valence shells
– Cation – positive ion loses electron – metal
– Anion – negative ion gains electron – nonmetal
• Stable Octet
– atoms gain stability by completing their valence shell
– this is done when shell is filled with eight electrons
• Ionic Compound (salt)
– formed from electrovalent attraction of cation for anion
Created by C. Ippolito
Dec 2006
Lewis Dot Diagrams
• used to represent valence shells of atoms
– kernel – nucleus and all inner energy levels
• represented by the element’s symbol
– valence electrons
• represented by dots surrounding the symbol
• determined by the Group or Family in periodic table
Created by C. Ippolito
Dec 2006
Dot Diagrams of Atoms
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14
• Group 18
Created by C. Ippolito
Dec 2006
Dot Diagrams of Ions
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14 – no ion
• Group 18 – no ion
Created by C. Ippolito
Dec 2006
Covalent Bond
• atoms share electrons to complete valence shell
– molecular substance – atoms held together by covalent bonds
• Nonpolar Covalent Bond
– electrons are shared equally – electronegativity <1.3
• Polar Covalent Bond
– electrons are shared unequally
– electronegativity 1.3<<1.67
• Dipole
– molecule has a slightly positive side (δ+)
– molecule has a slightly negative side (δ-)
Created by C. Ippolito
Dec 2006
Nonpolar Covalent Bond
Representations
• Molecular Formula
• Dot Diagram
• Structural Formula
Created by C. Ippolito
Dec 2006
Multiple Covalent Bonds
• Single Bond
– 1 electron pair shared
• Double Bond
– 2 electron pairs shared
• Triple Bond
– 3 electron pairs shared
Created by C. Ippolito
Dec 2006
Hybridization
• rearrangement of electrons within the
valence orbitals during chemical reactions
– sp hybridization in carbon atom
• 1s22s22p2 configuration is changed in bonding
• one 2s electron is “elevated” to “equalize” all 2
orbitals
– 1s22spx1spy1spz1
Created by C. Ippolito
Dec 2006
Resonance
• explains structures that experimentally do
not conform to dot diagrams
– electrons are seen to move from one bond to
another bond and back again
– they “resonate”
Created by C. Ippolito
Dec 2006
VSEPR Modeling
• Valence Shell Electron Pair Repulsion
– used to explain shapes of molecules
– bonded atom’s electron clouds balance forces of
repulsion and attraction
– this “spaces” them apart as far as they possible
can be from each other
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Tetrahedral Shape
– bond angle 109.47o
– CH4
• Trigonal Pyramidal Shape
– bond angle 107o
– NH3
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Trigonal Planar Shape
– bond angle 120o
– SO3
• Bent Shape
– bond angle 105o
– H2O
• Linear Shape
– bond angle 180o
Created by C. Ippolito
Dec 2006
Hydrogen Bonding
• special attraction between dipoles and compounds
with hydrogen
– hydrogen atom with (δ+) slight positive charge forms
weak bond with highly electronegative atoms in other
molecules that have (δ-) slight negative charge
• special properties of water
– ice less dense than water
– high heat of vaporization (cooling property)
• holds DNA molecule halves together allowing replication
Created by C. Ippolito
Dec 2006
Metallic Bond
• metal atoms in solid and liquid state
– “positive ions” in a “sea” of free flowing
electrons
Created by C. Ippolito
Dec 2006
Network Solids
• covalent crystals
– atoms continuously bonded in a definite pattern
– “one giant” molecule
• very hard
• very high melting points
• poor conductors
Created by C. Ippolito
Dec 2006
Ionic Crystals
• ions packed in a regular pattern
– each anion is surrounded by cations
– each cation surrounded by anions
• high melting point
• nonconductive as solid
• conductive as liquid or dissolved
– because “lattice” structure is broken
Created by C. Ippolito
Dec 2006
Slide 8
Chemical Bonding
Objectives:
1.
describe the nature of a chemical bond and its relationship to
valence electrons
2.
compare ionic and covalent bonding
3.
use Lewis Dot Diagrams to represent ionic and covalent compounds
4.
describe the relationship between molecular polarity and bond
polarity
5.
explain the nature and effects of metallic bonding, hydrogen
bonding, and van der Waals forces
6.
compare the structure and properties of polar and nonpolar
molecules
7.
compare the four classes of solids: ionic, molecular, metallic, and
network
Created by C. Ippolito
Dec 2006
Chemical Bonding
• Chemical Bond
– force of attraction that holds atoms together to form
compounds
• Types of Bonds
–
–
–
–
Ionic Bond – transfer electrons – electronegativity >1.67
Covalent Bond – share electrons – electronegativity <1.67
Metallic Bond – free moving electrons in “cloud”
Network Bond – extended covalent bonds
Created by C. Ippolito
Dec 2006
Ionic Bonds
• electrons transferred from one element to another
to complete their valence shells
– Cation – positive ion loses electron – metal
– Anion – negative ion gains electron – nonmetal
• Stable Octet
– atoms gain stability by completing their valence shell
– this is done when shell is filled with eight electrons
• Ionic Compound (salt)
– formed from electrovalent attraction of cation for anion
Created by C. Ippolito
Dec 2006
Lewis Dot Diagrams
• used to represent valence shells of atoms
– kernel – nucleus and all inner energy levels
• represented by the element’s symbol
– valence electrons
• represented by dots surrounding the symbol
• determined by the Group or Family in periodic table
Created by C. Ippolito
Dec 2006
Dot Diagrams of Atoms
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14
• Group 18
Created by C. Ippolito
Dec 2006
Dot Diagrams of Ions
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14 – no ion
• Group 18 – no ion
Created by C. Ippolito
Dec 2006
Covalent Bond
• atoms share electrons to complete valence shell
– molecular substance – atoms held together by covalent bonds
• Nonpolar Covalent Bond
– electrons are shared equally – electronegativity <1.3
• Polar Covalent Bond
– electrons are shared unequally
– electronegativity 1.3<<1.67
• Dipole
– molecule has a slightly positive side (δ+)
– molecule has a slightly negative side (δ-)
Created by C. Ippolito
Dec 2006
Nonpolar Covalent Bond
Representations
• Molecular Formula
• Dot Diagram
• Structural Formula
Created by C. Ippolito
Dec 2006
Multiple Covalent Bonds
• Single Bond
– 1 electron pair shared
• Double Bond
– 2 electron pairs shared
• Triple Bond
– 3 electron pairs shared
Created by C. Ippolito
Dec 2006
Hybridization
• rearrangement of electrons within the
valence orbitals during chemical reactions
– sp hybridization in carbon atom
• 1s22s22p2 configuration is changed in bonding
• one 2s electron is “elevated” to “equalize” all 2
orbitals
– 1s22spx1spy1spz1
Created by C. Ippolito
Dec 2006
Resonance
• explains structures that experimentally do
not conform to dot diagrams
– electrons are seen to move from one bond to
another bond and back again
– they “resonate”
Created by C. Ippolito
Dec 2006
VSEPR Modeling
• Valence Shell Electron Pair Repulsion
– used to explain shapes of molecules
– bonded atom’s electron clouds balance forces of
repulsion and attraction
– this “spaces” them apart as far as they possible
can be from each other
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Tetrahedral Shape
– bond angle 109.47o
– CH4
• Trigonal Pyramidal Shape
– bond angle 107o
– NH3
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Trigonal Planar Shape
– bond angle 120o
– SO3
• Bent Shape
– bond angle 105o
– H2O
• Linear Shape
– bond angle 180o
Created by C. Ippolito
Dec 2006
Hydrogen Bonding
• special attraction between dipoles and compounds
with hydrogen
– hydrogen atom with (δ+) slight positive charge forms
weak bond with highly electronegative atoms in other
molecules that have (δ-) slight negative charge
• special properties of water
– ice less dense than water
– high heat of vaporization (cooling property)
• holds DNA molecule halves together allowing replication
Created by C. Ippolito
Dec 2006
Metallic Bond
• metal atoms in solid and liquid state
– “positive ions” in a “sea” of free flowing
electrons
Created by C. Ippolito
Dec 2006
Network Solids
• covalent crystals
– atoms continuously bonded in a definite pattern
– “one giant” molecule
• very hard
• very high melting points
• poor conductors
Created by C. Ippolito
Dec 2006
Ionic Crystals
• ions packed in a regular pattern
– each anion is surrounded by cations
– each cation surrounded by anions
• high melting point
• nonconductive as solid
• conductive as liquid or dissolved
– because “lattice” structure is broken
Created by C. Ippolito
Dec 2006
Slide 9
Chemical Bonding
Objectives:
1.
describe the nature of a chemical bond and its relationship to
valence electrons
2.
compare ionic and covalent bonding
3.
use Lewis Dot Diagrams to represent ionic and covalent compounds
4.
describe the relationship between molecular polarity and bond
polarity
5.
explain the nature and effects of metallic bonding, hydrogen
bonding, and van der Waals forces
6.
compare the structure and properties of polar and nonpolar
molecules
7.
compare the four classes of solids: ionic, molecular, metallic, and
network
Created by C. Ippolito
Dec 2006
Chemical Bonding
• Chemical Bond
– force of attraction that holds atoms together to form
compounds
• Types of Bonds
–
–
–
–
Ionic Bond – transfer electrons – electronegativity >1.67
Covalent Bond – share electrons – electronegativity <1.67
Metallic Bond – free moving electrons in “cloud”
Network Bond – extended covalent bonds
Created by C. Ippolito
Dec 2006
Ionic Bonds
• electrons transferred from one element to another
to complete their valence shells
– Cation – positive ion loses electron – metal
– Anion – negative ion gains electron – nonmetal
• Stable Octet
– atoms gain stability by completing their valence shell
– this is done when shell is filled with eight electrons
• Ionic Compound (salt)
– formed from electrovalent attraction of cation for anion
Created by C. Ippolito
Dec 2006
Lewis Dot Diagrams
• used to represent valence shells of atoms
– kernel – nucleus and all inner energy levels
• represented by the element’s symbol
– valence electrons
• represented by dots surrounding the symbol
• determined by the Group or Family in periodic table
Created by C. Ippolito
Dec 2006
Dot Diagrams of Atoms
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14
• Group 18
Created by C. Ippolito
Dec 2006
Dot Diagrams of Ions
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14 – no ion
• Group 18 – no ion
Created by C. Ippolito
Dec 2006
Covalent Bond
• atoms share electrons to complete valence shell
– molecular substance – atoms held together by covalent bonds
• Nonpolar Covalent Bond
– electrons are shared equally – electronegativity <1.3
• Polar Covalent Bond
– electrons are shared unequally
– electronegativity 1.3<<1.67
• Dipole
– molecule has a slightly positive side (δ+)
– molecule has a slightly negative side (δ-)
Created by C. Ippolito
Dec 2006
Nonpolar Covalent Bond
Representations
• Molecular Formula
• Dot Diagram
• Structural Formula
Created by C. Ippolito
Dec 2006
Multiple Covalent Bonds
• Single Bond
– 1 electron pair shared
• Double Bond
– 2 electron pairs shared
• Triple Bond
– 3 electron pairs shared
Created by C. Ippolito
Dec 2006
Hybridization
• rearrangement of electrons within the
valence orbitals during chemical reactions
– sp hybridization in carbon atom
• 1s22s22p2 configuration is changed in bonding
• one 2s electron is “elevated” to “equalize” all 2
orbitals
– 1s22spx1spy1spz1
Created by C. Ippolito
Dec 2006
Resonance
• explains structures that experimentally do
not conform to dot diagrams
– electrons are seen to move from one bond to
another bond and back again
– they “resonate”
Created by C. Ippolito
Dec 2006
VSEPR Modeling
• Valence Shell Electron Pair Repulsion
– used to explain shapes of molecules
– bonded atom’s electron clouds balance forces of
repulsion and attraction
– this “spaces” them apart as far as they possible
can be from each other
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Tetrahedral Shape
– bond angle 109.47o
– CH4
• Trigonal Pyramidal Shape
– bond angle 107o
– NH3
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Trigonal Planar Shape
– bond angle 120o
– SO3
• Bent Shape
– bond angle 105o
– H2O
• Linear Shape
– bond angle 180o
Created by C. Ippolito
Dec 2006
Hydrogen Bonding
• special attraction between dipoles and compounds
with hydrogen
– hydrogen atom with (δ+) slight positive charge forms
weak bond with highly electronegative atoms in other
molecules that have (δ-) slight negative charge
• special properties of water
– ice less dense than water
– high heat of vaporization (cooling property)
• holds DNA molecule halves together allowing replication
Created by C. Ippolito
Dec 2006
Metallic Bond
• metal atoms in solid and liquid state
– “positive ions” in a “sea” of free flowing
electrons
Created by C. Ippolito
Dec 2006
Network Solids
• covalent crystals
– atoms continuously bonded in a definite pattern
– “one giant” molecule
• very hard
• very high melting points
• poor conductors
Created by C. Ippolito
Dec 2006
Ionic Crystals
• ions packed in a regular pattern
– each anion is surrounded by cations
– each cation surrounded by anions
• high melting point
• nonconductive as solid
• conductive as liquid or dissolved
– because “lattice” structure is broken
Created by C. Ippolito
Dec 2006
Slide 10
Chemical Bonding
Objectives:
1.
describe the nature of a chemical bond and its relationship to
valence electrons
2.
compare ionic and covalent bonding
3.
use Lewis Dot Diagrams to represent ionic and covalent compounds
4.
describe the relationship between molecular polarity and bond
polarity
5.
explain the nature and effects of metallic bonding, hydrogen
bonding, and van der Waals forces
6.
compare the structure and properties of polar and nonpolar
molecules
7.
compare the four classes of solids: ionic, molecular, metallic, and
network
Created by C. Ippolito
Dec 2006
Chemical Bonding
• Chemical Bond
– force of attraction that holds atoms together to form
compounds
• Types of Bonds
–
–
–
–
Ionic Bond – transfer electrons – electronegativity >1.67
Covalent Bond – share electrons – electronegativity <1.67
Metallic Bond – free moving electrons in “cloud”
Network Bond – extended covalent bonds
Created by C. Ippolito
Dec 2006
Ionic Bonds
• electrons transferred from one element to another
to complete their valence shells
– Cation – positive ion loses electron – metal
– Anion – negative ion gains electron – nonmetal
• Stable Octet
– atoms gain stability by completing their valence shell
– this is done when shell is filled with eight electrons
• Ionic Compound (salt)
– formed from electrovalent attraction of cation for anion
Created by C. Ippolito
Dec 2006
Lewis Dot Diagrams
• used to represent valence shells of atoms
– kernel – nucleus and all inner energy levels
• represented by the element’s symbol
– valence electrons
• represented by dots surrounding the symbol
• determined by the Group or Family in periodic table
Created by C. Ippolito
Dec 2006
Dot Diagrams of Atoms
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14
• Group 18
Created by C. Ippolito
Dec 2006
Dot Diagrams of Ions
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14 – no ion
• Group 18 – no ion
Created by C. Ippolito
Dec 2006
Covalent Bond
• atoms share electrons to complete valence shell
– molecular substance – atoms held together by covalent bonds
• Nonpolar Covalent Bond
– electrons are shared equally – electronegativity <1.3
• Polar Covalent Bond
– electrons are shared unequally
– electronegativity 1.3<<1.67
• Dipole
– molecule has a slightly positive side (δ+)
– molecule has a slightly negative side (δ-)
Created by C. Ippolito
Dec 2006
Nonpolar Covalent Bond
Representations
• Molecular Formula
• Dot Diagram
• Structural Formula
Created by C. Ippolito
Dec 2006
Multiple Covalent Bonds
• Single Bond
– 1 electron pair shared
• Double Bond
– 2 electron pairs shared
• Triple Bond
– 3 electron pairs shared
Created by C. Ippolito
Dec 2006
Hybridization
• rearrangement of electrons within the
valence orbitals during chemical reactions
– sp hybridization in carbon atom
• 1s22s22p2 configuration is changed in bonding
• one 2s electron is “elevated” to “equalize” all 2
orbitals
– 1s22spx1spy1spz1
Created by C. Ippolito
Dec 2006
Resonance
• explains structures that experimentally do
not conform to dot diagrams
– electrons are seen to move from one bond to
another bond and back again
– they “resonate”
Created by C. Ippolito
Dec 2006
VSEPR Modeling
• Valence Shell Electron Pair Repulsion
– used to explain shapes of molecules
– bonded atom’s electron clouds balance forces of
repulsion and attraction
– this “spaces” them apart as far as they possible
can be from each other
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Tetrahedral Shape
– bond angle 109.47o
– CH4
• Trigonal Pyramidal Shape
– bond angle 107o
– NH3
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Trigonal Planar Shape
– bond angle 120o
– SO3
• Bent Shape
– bond angle 105o
– H2O
• Linear Shape
– bond angle 180o
Created by C. Ippolito
Dec 2006
Hydrogen Bonding
• special attraction between dipoles and compounds
with hydrogen
– hydrogen atom with (δ+) slight positive charge forms
weak bond with highly electronegative atoms in other
molecules that have (δ-) slight negative charge
• special properties of water
– ice less dense than water
– high heat of vaporization (cooling property)
• holds DNA molecule halves together allowing replication
Created by C. Ippolito
Dec 2006
Metallic Bond
• metal atoms in solid and liquid state
– “positive ions” in a “sea” of free flowing
electrons
Created by C. Ippolito
Dec 2006
Network Solids
• covalent crystals
– atoms continuously bonded in a definite pattern
– “one giant” molecule
• very hard
• very high melting points
• poor conductors
Created by C. Ippolito
Dec 2006
Ionic Crystals
• ions packed in a regular pattern
– each anion is surrounded by cations
– each cation surrounded by anions
• high melting point
• nonconductive as solid
• conductive as liquid or dissolved
– because “lattice” structure is broken
Created by C. Ippolito
Dec 2006
Slide 11
Chemical Bonding
Objectives:
1.
describe the nature of a chemical bond and its relationship to
valence electrons
2.
compare ionic and covalent bonding
3.
use Lewis Dot Diagrams to represent ionic and covalent compounds
4.
describe the relationship between molecular polarity and bond
polarity
5.
explain the nature and effects of metallic bonding, hydrogen
bonding, and van der Waals forces
6.
compare the structure and properties of polar and nonpolar
molecules
7.
compare the four classes of solids: ionic, molecular, metallic, and
network
Created by C. Ippolito
Dec 2006
Chemical Bonding
• Chemical Bond
– force of attraction that holds atoms together to form
compounds
• Types of Bonds
–
–
–
–
Ionic Bond – transfer electrons – electronegativity >1.67
Covalent Bond – share electrons – electronegativity <1.67
Metallic Bond – free moving electrons in “cloud”
Network Bond – extended covalent bonds
Created by C. Ippolito
Dec 2006
Ionic Bonds
• electrons transferred from one element to another
to complete their valence shells
– Cation – positive ion loses electron – metal
– Anion – negative ion gains electron – nonmetal
• Stable Octet
– atoms gain stability by completing their valence shell
– this is done when shell is filled with eight electrons
• Ionic Compound (salt)
– formed from electrovalent attraction of cation for anion
Created by C. Ippolito
Dec 2006
Lewis Dot Diagrams
• used to represent valence shells of atoms
– kernel – nucleus and all inner energy levels
• represented by the element’s symbol
– valence electrons
• represented by dots surrounding the symbol
• determined by the Group or Family in periodic table
Created by C. Ippolito
Dec 2006
Dot Diagrams of Atoms
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14
• Group 18
Created by C. Ippolito
Dec 2006
Dot Diagrams of Ions
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14 – no ion
• Group 18 – no ion
Created by C. Ippolito
Dec 2006
Covalent Bond
• atoms share electrons to complete valence shell
– molecular substance – atoms held together by covalent bonds
• Nonpolar Covalent Bond
– electrons are shared equally – electronegativity <1.3
• Polar Covalent Bond
– electrons are shared unequally
– electronegativity 1.3<<1.67
• Dipole
– molecule has a slightly positive side (δ+)
– molecule has a slightly negative side (δ-)
Created by C. Ippolito
Dec 2006
Nonpolar Covalent Bond
Representations
• Molecular Formula
• Dot Diagram
• Structural Formula
Created by C. Ippolito
Dec 2006
Multiple Covalent Bonds
• Single Bond
– 1 electron pair shared
• Double Bond
– 2 electron pairs shared
• Triple Bond
– 3 electron pairs shared
Created by C. Ippolito
Dec 2006
Hybridization
• rearrangement of electrons within the
valence orbitals during chemical reactions
– sp hybridization in carbon atom
• 1s22s22p2 configuration is changed in bonding
• one 2s electron is “elevated” to “equalize” all 2
orbitals
– 1s22spx1spy1spz1
Created by C. Ippolito
Dec 2006
Resonance
• explains structures that experimentally do
not conform to dot diagrams
– electrons are seen to move from one bond to
another bond and back again
– they “resonate”
Created by C. Ippolito
Dec 2006
VSEPR Modeling
• Valence Shell Electron Pair Repulsion
– used to explain shapes of molecules
– bonded atom’s electron clouds balance forces of
repulsion and attraction
– this “spaces” them apart as far as they possible
can be from each other
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Tetrahedral Shape
– bond angle 109.47o
– CH4
• Trigonal Pyramidal Shape
– bond angle 107o
– NH3
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Trigonal Planar Shape
– bond angle 120o
– SO3
• Bent Shape
– bond angle 105o
– H2O
• Linear Shape
– bond angle 180o
Created by C. Ippolito
Dec 2006
Hydrogen Bonding
• special attraction between dipoles and compounds
with hydrogen
– hydrogen atom with (δ+) slight positive charge forms
weak bond with highly electronegative atoms in other
molecules that have (δ-) slight negative charge
• special properties of water
– ice less dense than water
– high heat of vaporization (cooling property)
• holds DNA molecule halves together allowing replication
Created by C. Ippolito
Dec 2006
Metallic Bond
• metal atoms in solid and liquid state
– “positive ions” in a “sea” of free flowing
electrons
Created by C. Ippolito
Dec 2006
Network Solids
• covalent crystals
– atoms continuously bonded in a definite pattern
– “one giant” molecule
• very hard
• very high melting points
• poor conductors
Created by C. Ippolito
Dec 2006
Ionic Crystals
• ions packed in a regular pattern
– each anion is surrounded by cations
– each cation surrounded by anions
• high melting point
• nonconductive as solid
• conductive as liquid or dissolved
– because “lattice” structure is broken
Created by C. Ippolito
Dec 2006
Slide 12
Chemical Bonding
Objectives:
1.
describe the nature of a chemical bond and its relationship to
valence electrons
2.
compare ionic and covalent bonding
3.
use Lewis Dot Diagrams to represent ionic and covalent compounds
4.
describe the relationship between molecular polarity and bond
polarity
5.
explain the nature and effects of metallic bonding, hydrogen
bonding, and van der Waals forces
6.
compare the structure and properties of polar and nonpolar
molecules
7.
compare the four classes of solids: ionic, molecular, metallic, and
network
Created by C. Ippolito
Dec 2006
Chemical Bonding
• Chemical Bond
– force of attraction that holds atoms together to form
compounds
• Types of Bonds
–
–
–
–
Ionic Bond – transfer electrons – electronegativity >1.67
Covalent Bond – share electrons – electronegativity <1.67
Metallic Bond – free moving electrons in “cloud”
Network Bond – extended covalent bonds
Created by C. Ippolito
Dec 2006
Ionic Bonds
• electrons transferred from one element to another
to complete their valence shells
– Cation – positive ion loses electron – metal
– Anion – negative ion gains electron – nonmetal
• Stable Octet
– atoms gain stability by completing their valence shell
– this is done when shell is filled with eight electrons
• Ionic Compound (salt)
– formed from electrovalent attraction of cation for anion
Created by C. Ippolito
Dec 2006
Lewis Dot Diagrams
• used to represent valence shells of atoms
– kernel – nucleus and all inner energy levels
• represented by the element’s symbol
– valence electrons
• represented by dots surrounding the symbol
• determined by the Group or Family in periodic table
Created by C. Ippolito
Dec 2006
Dot Diagrams of Atoms
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14
• Group 18
Created by C. Ippolito
Dec 2006
Dot Diagrams of Ions
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14 – no ion
• Group 18 – no ion
Created by C. Ippolito
Dec 2006
Covalent Bond
• atoms share electrons to complete valence shell
– molecular substance – atoms held together by covalent bonds
• Nonpolar Covalent Bond
– electrons are shared equally – electronegativity <1.3
• Polar Covalent Bond
– electrons are shared unequally
– electronegativity 1.3<<1.67
• Dipole
– molecule has a slightly positive side (δ+)
– molecule has a slightly negative side (δ-)
Created by C. Ippolito
Dec 2006
Nonpolar Covalent Bond
Representations
• Molecular Formula
• Dot Diagram
• Structural Formula
Created by C. Ippolito
Dec 2006
Multiple Covalent Bonds
• Single Bond
– 1 electron pair shared
• Double Bond
– 2 electron pairs shared
• Triple Bond
– 3 electron pairs shared
Created by C. Ippolito
Dec 2006
Hybridization
• rearrangement of electrons within the
valence orbitals during chemical reactions
– sp hybridization in carbon atom
• 1s22s22p2 configuration is changed in bonding
• one 2s electron is “elevated” to “equalize” all 2
orbitals
– 1s22spx1spy1spz1
Created by C. Ippolito
Dec 2006
Resonance
• explains structures that experimentally do
not conform to dot diagrams
– electrons are seen to move from one bond to
another bond and back again
– they “resonate”
Created by C. Ippolito
Dec 2006
VSEPR Modeling
• Valence Shell Electron Pair Repulsion
– used to explain shapes of molecules
– bonded atom’s electron clouds balance forces of
repulsion and attraction
– this “spaces” them apart as far as they possible
can be from each other
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Tetrahedral Shape
– bond angle 109.47o
– CH4
• Trigonal Pyramidal Shape
– bond angle 107o
– NH3
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Trigonal Planar Shape
– bond angle 120o
– SO3
• Bent Shape
– bond angle 105o
– H2O
• Linear Shape
– bond angle 180o
Created by C. Ippolito
Dec 2006
Hydrogen Bonding
• special attraction between dipoles and compounds
with hydrogen
– hydrogen atom with (δ+) slight positive charge forms
weak bond with highly electronegative atoms in other
molecules that have (δ-) slight negative charge
• special properties of water
– ice less dense than water
– high heat of vaporization (cooling property)
• holds DNA molecule halves together allowing replication
Created by C. Ippolito
Dec 2006
Metallic Bond
• metal atoms in solid and liquid state
– “positive ions” in a “sea” of free flowing
electrons
Created by C. Ippolito
Dec 2006
Network Solids
• covalent crystals
– atoms continuously bonded in a definite pattern
– “one giant” molecule
• very hard
• very high melting points
• poor conductors
Created by C. Ippolito
Dec 2006
Ionic Crystals
• ions packed in a regular pattern
– each anion is surrounded by cations
– each cation surrounded by anions
• high melting point
• nonconductive as solid
• conductive as liquid or dissolved
– because “lattice” structure is broken
Created by C. Ippolito
Dec 2006
Slide 13
Chemical Bonding
Objectives:
1.
describe the nature of a chemical bond and its relationship to
valence electrons
2.
compare ionic and covalent bonding
3.
use Lewis Dot Diagrams to represent ionic and covalent compounds
4.
describe the relationship between molecular polarity and bond
polarity
5.
explain the nature and effects of metallic bonding, hydrogen
bonding, and van der Waals forces
6.
compare the structure and properties of polar and nonpolar
molecules
7.
compare the four classes of solids: ionic, molecular, metallic, and
network
Created by C. Ippolito
Dec 2006
Chemical Bonding
• Chemical Bond
– force of attraction that holds atoms together to form
compounds
• Types of Bonds
–
–
–
–
Ionic Bond – transfer electrons – electronegativity >1.67
Covalent Bond – share electrons – electronegativity <1.67
Metallic Bond – free moving electrons in “cloud”
Network Bond – extended covalent bonds
Created by C. Ippolito
Dec 2006
Ionic Bonds
• electrons transferred from one element to another
to complete their valence shells
– Cation – positive ion loses electron – metal
– Anion – negative ion gains electron – nonmetal
• Stable Octet
– atoms gain stability by completing their valence shell
– this is done when shell is filled with eight electrons
• Ionic Compound (salt)
– formed from electrovalent attraction of cation for anion
Created by C. Ippolito
Dec 2006
Lewis Dot Diagrams
• used to represent valence shells of atoms
– kernel – nucleus and all inner energy levels
• represented by the element’s symbol
– valence electrons
• represented by dots surrounding the symbol
• determined by the Group or Family in periodic table
Created by C. Ippolito
Dec 2006
Dot Diagrams of Atoms
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14
• Group 18
Created by C. Ippolito
Dec 2006
Dot Diagrams of Ions
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14 – no ion
• Group 18 – no ion
Created by C. Ippolito
Dec 2006
Covalent Bond
• atoms share electrons to complete valence shell
– molecular substance – atoms held together by covalent bonds
• Nonpolar Covalent Bond
– electrons are shared equally – electronegativity <1.3
• Polar Covalent Bond
– electrons are shared unequally
– electronegativity 1.3<<1.67
• Dipole
– molecule has a slightly positive side (δ+)
– molecule has a slightly negative side (δ-)
Created by C. Ippolito
Dec 2006
Nonpolar Covalent Bond
Representations
• Molecular Formula
• Dot Diagram
• Structural Formula
Created by C. Ippolito
Dec 2006
Multiple Covalent Bonds
• Single Bond
– 1 electron pair shared
• Double Bond
– 2 electron pairs shared
• Triple Bond
– 3 electron pairs shared
Created by C. Ippolito
Dec 2006
Hybridization
• rearrangement of electrons within the
valence orbitals during chemical reactions
– sp hybridization in carbon atom
• 1s22s22p2 configuration is changed in bonding
• one 2s electron is “elevated” to “equalize” all 2
orbitals
– 1s22spx1spy1spz1
Created by C. Ippolito
Dec 2006
Resonance
• explains structures that experimentally do
not conform to dot diagrams
– electrons are seen to move from one bond to
another bond and back again
– they “resonate”
Created by C. Ippolito
Dec 2006
VSEPR Modeling
• Valence Shell Electron Pair Repulsion
– used to explain shapes of molecules
– bonded atom’s electron clouds balance forces of
repulsion and attraction
– this “spaces” them apart as far as they possible
can be from each other
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Tetrahedral Shape
– bond angle 109.47o
– CH4
• Trigonal Pyramidal Shape
– bond angle 107o
– NH3
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Trigonal Planar Shape
– bond angle 120o
– SO3
• Bent Shape
– bond angle 105o
– H2O
• Linear Shape
– bond angle 180o
Created by C. Ippolito
Dec 2006
Hydrogen Bonding
• special attraction between dipoles and compounds
with hydrogen
– hydrogen atom with (δ+) slight positive charge forms
weak bond with highly electronegative atoms in other
molecules that have (δ-) slight negative charge
• special properties of water
– ice less dense than water
– high heat of vaporization (cooling property)
• holds DNA molecule halves together allowing replication
Created by C. Ippolito
Dec 2006
Metallic Bond
• metal atoms in solid and liquid state
– “positive ions” in a “sea” of free flowing
electrons
Created by C. Ippolito
Dec 2006
Network Solids
• covalent crystals
– atoms continuously bonded in a definite pattern
– “one giant” molecule
• very hard
• very high melting points
• poor conductors
Created by C. Ippolito
Dec 2006
Ionic Crystals
• ions packed in a regular pattern
– each anion is surrounded by cations
– each cation surrounded by anions
• high melting point
• nonconductive as solid
• conductive as liquid or dissolved
– because “lattice” structure is broken
Created by C. Ippolito
Dec 2006
Slide 14
Chemical Bonding
Objectives:
1.
describe the nature of a chemical bond and its relationship to
valence electrons
2.
compare ionic and covalent bonding
3.
use Lewis Dot Diagrams to represent ionic and covalent compounds
4.
describe the relationship between molecular polarity and bond
polarity
5.
explain the nature and effects of metallic bonding, hydrogen
bonding, and van der Waals forces
6.
compare the structure and properties of polar and nonpolar
molecules
7.
compare the four classes of solids: ionic, molecular, metallic, and
network
Created by C. Ippolito
Dec 2006
Chemical Bonding
• Chemical Bond
– force of attraction that holds atoms together to form
compounds
• Types of Bonds
–
–
–
–
Ionic Bond – transfer electrons – electronegativity >1.67
Covalent Bond – share electrons – electronegativity <1.67
Metallic Bond – free moving electrons in “cloud”
Network Bond – extended covalent bonds
Created by C. Ippolito
Dec 2006
Ionic Bonds
• electrons transferred from one element to another
to complete their valence shells
– Cation – positive ion loses electron – metal
– Anion – negative ion gains electron – nonmetal
• Stable Octet
– atoms gain stability by completing their valence shell
– this is done when shell is filled with eight electrons
• Ionic Compound (salt)
– formed from electrovalent attraction of cation for anion
Created by C. Ippolito
Dec 2006
Lewis Dot Diagrams
• used to represent valence shells of atoms
– kernel – nucleus and all inner energy levels
• represented by the element’s symbol
– valence electrons
• represented by dots surrounding the symbol
• determined by the Group or Family in periodic table
Created by C. Ippolito
Dec 2006
Dot Diagrams of Atoms
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14
• Group 18
Created by C. Ippolito
Dec 2006
Dot Diagrams of Ions
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14 – no ion
• Group 18 – no ion
Created by C. Ippolito
Dec 2006
Covalent Bond
• atoms share electrons to complete valence shell
– molecular substance – atoms held together by covalent bonds
• Nonpolar Covalent Bond
– electrons are shared equally – electronegativity <1.3
• Polar Covalent Bond
– electrons are shared unequally
– electronegativity 1.3<<1.67
• Dipole
– molecule has a slightly positive side (δ+)
– molecule has a slightly negative side (δ-)
Created by C. Ippolito
Dec 2006
Nonpolar Covalent Bond
Representations
• Molecular Formula
• Dot Diagram
• Structural Formula
Created by C. Ippolito
Dec 2006
Multiple Covalent Bonds
• Single Bond
– 1 electron pair shared
• Double Bond
– 2 electron pairs shared
• Triple Bond
– 3 electron pairs shared
Created by C. Ippolito
Dec 2006
Hybridization
• rearrangement of electrons within the
valence orbitals during chemical reactions
– sp hybridization in carbon atom
• 1s22s22p2 configuration is changed in bonding
• one 2s electron is “elevated” to “equalize” all 2
orbitals
– 1s22spx1spy1spz1
Created by C. Ippolito
Dec 2006
Resonance
• explains structures that experimentally do
not conform to dot diagrams
– electrons are seen to move from one bond to
another bond and back again
– they “resonate”
Created by C. Ippolito
Dec 2006
VSEPR Modeling
• Valence Shell Electron Pair Repulsion
– used to explain shapes of molecules
– bonded atom’s electron clouds balance forces of
repulsion and attraction
– this “spaces” them apart as far as they possible
can be from each other
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Tetrahedral Shape
– bond angle 109.47o
– CH4
• Trigonal Pyramidal Shape
– bond angle 107o
– NH3
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Trigonal Planar Shape
– bond angle 120o
– SO3
• Bent Shape
– bond angle 105o
– H2O
• Linear Shape
– bond angle 180o
Created by C. Ippolito
Dec 2006
Hydrogen Bonding
• special attraction between dipoles and compounds
with hydrogen
– hydrogen atom with (δ+) slight positive charge forms
weak bond with highly electronegative atoms in other
molecules that have (δ-) slight negative charge
• special properties of water
– ice less dense than water
– high heat of vaporization (cooling property)
• holds DNA molecule halves together allowing replication
Created by C. Ippolito
Dec 2006
Metallic Bond
• metal atoms in solid and liquid state
– “positive ions” in a “sea” of free flowing
electrons
Created by C. Ippolito
Dec 2006
Network Solids
• covalent crystals
– atoms continuously bonded in a definite pattern
– “one giant” molecule
• very hard
• very high melting points
• poor conductors
Created by C. Ippolito
Dec 2006
Ionic Crystals
• ions packed in a regular pattern
– each anion is surrounded by cations
– each cation surrounded by anions
• high melting point
• nonconductive as solid
• conductive as liquid or dissolved
– because “lattice” structure is broken
Created by C. Ippolito
Dec 2006
Slide 15
Chemical Bonding
Objectives:
1.
describe the nature of a chemical bond and its relationship to
valence electrons
2.
compare ionic and covalent bonding
3.
use Lewis Dot Diagrams to represent ionic and covalent compounds
4.
describe the relationship between molecular polarity and bond
polarity
5.
explain the nature and effects of metallic bonding, hydrogen
bonding, and van der Waals forces
6.
compare the structure and properties of polar and nonpolar
molecules
7.
compare the four classes of solids: ionic, molecular, metallic, and
network
Created by C. Ippolito
Dec 2006
Chemical Bonding
• Chemical Bond
– force of attraction that holds atoms together to form
compounds
• Types of Bonds
–
–
–
–
Ionic Bond – transfer electrons – electronegativity >1.67
Covalent Bond – share electrons – electronegativity <1.67
Metallic Bond – free moving electrons in “cloud”
Network Bond – extended covalent bonds
Created by C. Ippolito
Dec 2006
Ionic Bonds
• electrons transferred from one element to another
to complete their valence shells
– Cation – positive ion loses electron – metal
– Anion – negative ion gains electron – nonmetal
• Stable Octet
– atoms gain stability by completing their valence shell
– this is done when shell is filled with eight electrons
• Ionic Compound (salt)
– formed from electrovalent attraction of cation for anion
Created by C. Ippolito
Dec 2006
Lewis Dot Diagrams
• used to represent valence shells of atoms
– kernel – nucleus and all inner energy levels
• represented by the element’s symbol
– valence electrons
• represented by dots surrounding the symbol
• determined by the Group or Family in periodic table
Created by C. Ippolito
Dec 2006
Dot Diagrams of Atoms
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14
• Group 18
Created by C. Ippolito
Dec 2006
Dot Diagrams of Ions
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14 – no ion
• Group 18 – no ion
Created by C. Ippolito
Dec 2006
Covalent Bond
• atoms share electrons to complete valence shell
– molecular substance – atoms held together by covalent bonds
• Nonpolar Covalent Bond
– electrons are shared equally – electronegativity <1.3
• Polar Covalent Bond
– electrons are shared unequally
– electronegativity 1.3<<1.67
• Dipole
– molecule has a slightly positive side (δ+)
– molecule has a slightly negative side (δ-)
Created by C. Ippolito
Dec 2006
Nonpolar Covalent Bond
Representations
• Molecular Formula
• Dot Diagram
• Structural Formula
Created by C. Ippolito
Dec 2006
Multiple Covalent Bonds
• Single Bond
– 1 electron pair shared
• Double Bond
– 2 electron pairs shared
• Triple Bond
– 3 electron pairs shared
Created by C. Ippolito
Dec 2006
Hybridization
• rearrangement of electrons within the
valence orbitals during chemical reactions
– sp hybridization in carbon atom
• 1s22s22p2 configuration is changed in bonding
• one 2s electron is “elevated” to “equalize” all 2
orbitals
– 1s22spx1spy1spz1
Created by C. Ippolito
Dec 2006
Resonance
• explains structures that experimentally do
not conform to dot diagrams
– electrons are seen to move from one bond to
another bond and back again
– they “resonate”
Created by C. Ippolito
Dec 2006
VSEPR Modeling
• Valence Shell Electron Pair Repulsion
– used to explain shapes of molecules
– bonded atom’s electron clouds balance forces of
repulsion and attraction
– this “spaces” them apart as far as they possible
can be from each other
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Tetrahedral Shape
– bond angle 109.47o
– CH4
• Trigonal Pyramidal Shape
– bond angle 107o
– NH3
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Trigonal Planar Shape
– bond angle 120o
– SO3
• Bent Shape
– bond angle 105o
– H2O
• Linear Shape
– bond angle 180o
Created by C. Ippolito
Dec 2006
Hydrogen Bonding
• special attraction between dipoles and compounds
with hydrogen
– hydrogen atom with (δ+) slight positive charge forms
weak bond with highly electronegative atoms in other
molecules that have (δ-) slight negative charge
• special properties of water
– ice less dense than water
– high heat of vaporization (cooling property)
• holds DNA molecule halves together allowing replication
Created by C. Ippolito
Dec 2006
Metallic Bond
• metal atoms in solid and liquid state
– “positive ions” in a “sea” of free flowing
electrons
Created by C. Ippolito
Dec 2006
Network Solids
• covalent crystals
– atoms continuously bonded in a definite pattern
– “one giant” molecule
• very hard
• very high melting points
• poor conductors
Created by C. Ippolito
Dec 2006
Ionic Crystals
• ions packed in a regular pattern
– each anion is surrounded by cations
– each cation surrounded by anions
• high melting point
• nonconductive as solid
• conductive as liquid or dissolved
– because “lattice” structure is broken
Created by C. Ippolito
Dec 2006
Slide 16
Chemical Bonding
Objectives:
1.
describe the nature of a chemical bond and its relationship to
valence electrons
2.
compare ionic and covalent bonding
3.
use Lewis Dot Diagrams to represent ionic and covalent compounds
4.
describe the relationship between molecular polarity and bond
polarity
5.
explain the nature and effects of metallic bonding, hydrogen
bonding, and van der Waals forces
6.
compare the structure and properties of polar and nonpolar
molecules
7.
compare the four classes of solids: ionic, molecular, metallic, and
network
Created by C. Ippolito
Dec 2006
Chemical Bonding
• Chemical Bond
– force of attraction that holds atoms together to form
compounds
• Types of Bonds
–
–
–
–
Ionic Bond – transfer electrons – electronegativity >1.67
Covalent Bond – share electrons – electronegativity <1.67
Metallic Bond – free moving electrons in “cloud”
Network Bond – extended covalent bonds
Created by C. Ippolito
Dec 2006
Ionic Bonds
• electrons transferred from one element to another
to complete their valence shells
– Cation – positive ion loses electron – metal
– Anion – negative ion gains electron – nonmetal
• Stable Octet
– atoms gain stability by completing their valence shell
– this is done when shell is filled with eight electrons
• Ionic Compound (salt)
– formed from electrovalent attraction of cation for anion
Created by C. Ippolito
Dec 2006
Lewis Dot Diagrams
• used to represent valence shells of atoms
– kernel – nucleus and all inner energy levels
• represented by the element’s symbol
– valence electrons
• represented by dots surrounding the symbol
• determined by the Group or Family in periodic table
Created by C. Ippolito
Dec 2006
Dot Diagrams of Atoms
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14
• Group 18
Created by C. Ippolito
Dec 2006
Dot Diagrams of Ions
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14 – no ion
• Group 18 – no ion
Created by C. Ippolito
Dec 2006
Covalent Bond
• atoms share electrons to complete valence shell
– molecular substance – atoms held together by covalent bonds
• Nonpolar Covalent Bond
– electrons are shared equally – electronegativity <1.3
• Polar Covalent Bond
– electrons are shared unequally
– electronegativity 1.3<<1.67
• Dipole
– molecule has a slightly positive side (δ+)
– molecule has a slightly negative side (δ-)
Created by C. Ippolito
Dec 2006
Nonpolar Covalent Bond
Representations
• Molecular Formula
• Dot Diagram
• Structural Formula
Created by C. Ippolito
Dec 2006
Multiple Covalent Bonds
• Single Bond
– 1 electron pair shared
• Double Bond
– 2 electron pairs shared
• Triple Bond
– 3 electron pairs shared
Created by C. Ippolito
Dec 2006
Hybridization
• rearrangement of electrons within the
valence orbitals during chemical reactions
– sp hybridization in carbon atom
• 1s22s22p2 configuration is changed in bonding
• one 2s electron is “elevated” to “equalize” all 2
orbitals
– 1s22spx1spy1spz1
Created by C. Ippolito
Dec 2006
Resonance
• explains structures that experimentally do
not conform to dot diagrams
– electrons are seen to move from one bond to
another bond and back again
– they “resonate”
Created by C. Ippolito
Dec 2006
VSEPR Modeling
• Valence Shell Electron Pair Repulsion
– used to explain shapes of molecules
– bonded atom’s electron clouds balance forces of
repulsion and attraction
– this “spaces” them apart as far as they possible
can be from each other
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Tetrahedral Shape
– bond angle 109.47o
– CH4
• Trigonal Pyramidal Shape
– bond angle 107o
– NH3
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Trigonal Planar Shape
– bond angle 120o
– SO3
• Bent Shape
– bond angle 105o
– H2O
• Linear Shape
– bond angle 180o
Created by C. Ippolito
Dec 2006
Hydrogen Bonding
• special attraction between dipoles and compounds
with hydrogen
– hydrogen atom with (δ+) slight positive charge forms
weak bond with highly electronegative atoms in other
molecules that have (δ-) slight negative charge
• special properties of water
– ice less dense than water
– high heat of vaporization (cooling property)
• holds DNA molecule halves together allowing replication
Created by C. Ippolito
Dec 2006
Metallic Bond
• metal atoms in solid and liquid state
– “positive ions” in a “sea” of free flowing
electrons
Created by C. Ippolito
Dec 2006
Network Solids
• covalent crystals
– atoms continuously bonded in a definite pattern
– “one giant” molecule
• very hard
• very high melting points
• poor conductors
Created by C. Ippolito
Dec 2006
Ionic Crystals
• ions packed in a regular pattern
– each anion is surrounded by cations
– each cation surrounded by anions
• high melting point
• nonconductive as solid
• conductive as liquid or dissolved
– because “lattice” structure is broken
Created by C. Ippolito
Dec 2006
Slide 17
Chemical Bonding
Objectives:
1.
describe the nature of a chemical bond and its relationship to
valence electrons
2.
compare ionic and covalent bonding
3.
use Lewis Dot Diagrams to represent ionic and covalent compounds
4.
describe the relationship between molecular polarity and bond
polarity
5.
explain the nature and effects of metallic bonding, hydrogen
bonding, and van der Waals forces
6.
compare the structure and properties of polar and nonpolar
molecules
7.
compare the four classes of solids: ionic, molecular, metallic, and
network
Created by C. Ippolito
Dec 2006
Chemical Bonding
• Chemical Bond
– force of attraction that holds atoms together to form
compounds
• Types of Bonds
–
–
–
–
Ionic Bond – transfer electrons – electronegativity >1.67
Covalent Bond – share electrons – electronegativity <1.67
Metallic Bond – free moving electrons in “cloud”
Network Bond – extended covalent bonds
Created by C. Ippolito
Dec 2006
Ionic Bonds
• electrons transferred from one element to another
to complete their valence shells
– Cation – positive ion loses electron – metal
– Anion – negative ion gains electron – nonmetal
• Stable Octet
– atoms gain stability by completing their valence shell
– this is done when shell is filled with eight electrons
• Ionic Compound (salt)
– formed from electrovalent attraction of cation for anion
Created by C. Ippolito
Dec 2006
Lewis Dot Diagrams
• used to represent valence shells of atoms
– kernel – nucleus and all inner energy levels
• represented by the element’s symbol
– valence electrons
• represented by dots surrounding the symbol
• determined by the Group or Family in periodic table
Created by C. Ippolito
Dec 2006
Dot Diagrams of Atoms
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14
• Group 18
Created by C. Ippolito
Dec 2006
Dot Diagrams of Ions
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14 – no ion
• Group 18 – no ion
Created by C. Ippolito
Dec 2006
Covalent Bond
• atoms share electrons to complete valence shell
– molecular substance – atoms held together by covalent bonds
• Nonpolar Covalent Bond
– electrons are shared equally – electronegativity <1.3
• Polar Covalent Bond
– electrons are shared unequally
– electronegativity 1.3<<1.67
• Dipole
– molecule has a slightly positive side (δ+)
– molecule has a slightly negative side (δ-)
Created by C. Ippolito
Dec 2006
Nonpolar Covalent Bond
Representations
• Molecular Formula
• Dot Diagram
• Structural Formula
Created by C. Ippolito
Dec 2006
Multiple Covalent Bonds
• Single Bond
– 1 electron pair shared
• Double Bond
– 2 electron pairs shared
• Triple Bond
– 3 electron pairs shared
Created by C. Ippolito
Dec 2006
Hybridization
• rearrangement of electrons within the
valence orbitals during chemical reactions
– sp hybridization in carbon atom
• 1s22s22p2 configuration is changed in bonding
• one 2s electron is “elevated” to “equalize” all 2
orbitals
– 1s22spx1spy1spz1
Created by C. Ippolito
Dec 2006
Resonance
• explains structures that experimentally do
not conform to dot diagrams
– electrons are seen to move from one bond to
another bond and back again
– they “resonate”
Created by C. Ippolito
Dec 2006
VSEPR Modeling
• Valence Shell Electron Pair Repulsion
– used to explain shapes of molecules
– bonded atom’s electron clouds balance forces of
repulsion and attraction
– this “spaces” them apart as far as they possible
can be from each other
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Tetrahedral Shape
– bond angle 109.47o
– CH4
• Trigonal Pyramidal Shape
– bond angle 107o
– NH3
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Trigonal Planar Shape
– bond angle 120o
– SO3
• Bent Shape
– bond angle 105o
– H2O
• Linear Shape
– bond angle 180o
Created by C. Ippolito
Dec 2006
Hydrogen Bonding
• special attraction between dipoles and compounds
with hydrogen
– hydrogen atom with (δ+) slight positive charge forms
weak bond with highly electronegative atoms in other
molecules that have (δ-) slight negative charge
• special properties of water
– ice less dense than water
– high heat of vaporization (cooling property)
• holds DNA molecule halves together allowing replication
Created by C. Ippolito
Dec 2006
Metallic Bond
• metal atoms in solid and liquid state
– “positive ions” in a “sea” of free flowing
electrons
Created by C. Ippolito
Dec 2006
Network Solids
• covalent crystals
– atoms continuously bonded in a definite pattern
– “one giant” molecule
• very hard
• very high melting points
• poor conductors
Created by C. Ippolito
Dec 2006
Ionic Crystals
• ions packed in a regular pattern
– each anion is surrounded by cations
– each cation surrounded by anions
• high melting point
• nonconductive as solid
• conductive as liquid or dissolved
– because “lattice” structure is broken
Created by C. Ippolito
Dec 2006
Slide 18
Chemical Bonding
Objectives:
1.
describe the nature of a chemical bond and its relationship to
valence electrons
2.
compare ionic and covalent bonding
3.
use Lewis Dot Diagrams to represent ionic and covalent compounds
4.
describe the relationship between molecular polarity and bond
polarity
5.
explain the nature and effects of metallic bonding, hydrogen
bonding, and van der Waals forces
6.
compare the structure and properties of polar and nonpolar
molecules
7.
compare the four classes of solids: ionic, molecular, metallic, and
network
Created by C. Ippolito
Dec 2006
Chemical Bonding
• Chemical Bond
– force of attraction that holds atoms together to form
compounds
• Types of Bonds
–
–
–
–
Ionic Bond – transfer electrons – electronegativity >1.67
Covalent Bond – share electrons – electronegativity <1.67
Metallic Bond – free moving electrons in “cloud”
Network Bond – extended covalent bonds
Created by C. Ippolito
Dec 2006
Ionic Bonds
• electrons transferred from one element to another
to complete their valence shells
– Cation – positive ion loses electron – metal
– Anion – negative ion gains electron – nonmetal
• Stable Octet
– atoms gain stability by completing their valence shell
– this is done when shell is filled with eight electrons
• Ionic Compound (salt)
– formed from electrovalent attraction of cation for anion
Created by C. Ippolito
Dec 2006
Lewis Dot Diagrams
• used to represent valence shells of atoms
– kernel – nucleus and all inner energy levels
• represented by the element’s symbol
– valence electrons
• represented by dots surrounding the symbol
• determined by the Group or Family in periodic table
Created by C. Ippolito
Dec 2006
Dot Diagrams of Atoms
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14
• Group 18
Created by C. Ippolito
Dec 2006
Dot Diagrams of Ions
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14 – no ion
• Group 18 – no ion
Created by C. Ippolito
Dec 2006
Covalent Bond
• atoms share electrons to complete valence shell
– molecular substance – atoms held together by covalent bonds
• Nonpolar Covalent Bond
– electrons are shared equally – electronegativity <1.3
• Polar Covalent Bond
– electrons are shared unequally
– electronegativity 1.3<<1.67
• Dipole
– molecule has a slightly positive side (δ+)
– molecule has a slightly negative side (δ-)
Created by C. Ippolito
Dec 2006
Nonpolar Covalent Bond
Representations
• Molecular Formula
• Dot Diagram
• Structural Formula
Created by C. Ippolito
Dec 2006
Multiple Covalent Bonds
• Single Bond
– 1 electron pair shared
• Double Bond
– 2 electron pairs shared
• Triple Bond
– 3 electron pairs shared
Created by C. Ippolito
Dec 2006
Hybridization
• rearrangement of electrons within the
valence orbitals during chemical reactions
– sp hybridization in carbon atom
• 1s22s22p2 configuration is changed in bonding
• one 2s electron is “elevated” to “equalize” all 2
orbitals
– 1s22spx1spy1spz1
Created by C. Ippolito
Dec 2006
Resonance
• explains structures that experimentally do
not conform to dot diagrams
– electrons are seen to move from one bond to
another bond and back again
– they “resonate”
Created by C. Ippolito
Dec 2006
VSEPR Modeling
• Valence Shell Electron Pair Repulsion
– used to explain shapes of molecules
– bonded atom’s electron clouds balance forces of
repulsion and attraction
– this “spaces” them apart as far as they possible
can be from each other
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Tetrahedral Shape
– bond angle 109.47o
– CH4
• Trigonal Pyramidal Shape
– bond angle 107o
– NH3
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Trigonal Planar Shape
– bond angle 120o
– SO3
• Bent Shape
– bond angle 105o
– H2O
• Linear Shape
– bond angle 180o
Created by C. Ippolito
Dec 2006
Hydrogen Bonding
• special attraction between dipoles and compounds
with hydrogen
– hydrogen atom with (δ+) slight positive charge forms
weak bond with highly electronegative atoms in other
molecules that have (δ-) slight negative charge
• special properties of water
– ice less dense than water
– high heat of vaporization (cooling property)
• holds DNA molecule halves together allowing replication
Created by C. Ippolito
Dec 2006
Metallic Bond
• metal atoms in solid and liquid state
– “positive ions” in a “sea” of free flowing
electrons
Created by C. Ippolito
Dec 2006
Network Solids
• covalent crystals
– atoms continuously bonded in a definite pattern
– “one giant” molecule
• very hard
• very high melting points
• poor conductors
Created by C. Ippolito
Dec 2006
Ionic Crystals
• ions packed in a regular pattern
– each anion is surrounded by cations
– each cation surrounded by anions
• high melting point
• nonconductive as solid
• conductive as liquid or dissolved
– because “lattice” structure is broken
Created by C. Ippolito
Dec 2006
Chemical Bonding
Objectives:
1.
describe the nature of a chemical bond and its relationship to
valence electrons
2.
compare ionic and covalent bonding
3.
use Lewis Dot Diagrams to represent ionic and covalent compounds
4.
describe the relationship between molecular polarity and bond
polarity
5.
explain the nature and effects of metallic bonding, hydrogen
bonding, and van der Waals forces
6.
compare the structure and properties of polar and nonpolar
molecules
7.
compare the four classes of solids: ionic, molecular, metallic, and
network
Created by C. Ippolito
Dec 2006
Chemical Bonding
• Chemical Bond
– force of attraction that holds atoms together to form
compounds
• Types of Bonds
–
–
–
–
Ionic Bond – transfer electrons – electronegativity >1.67
Covalent Bond – share electrons – electronegativity <1.67
Metallic Bond – free moving electrons in “cloud”
Network Bond – extended covalent bonds
Created by C. Ippolito
Dec 2006
Ionic Bonds
• electrons transferred from one element to another
to complete their valence shells
– Cation – positive ion loses electron – metal
– Anion – negative ion gains electron – nonmetal
• Stable Octet
– atoms gain stability by completing their valence shell
– this is done when shell is filled with eight electrons
• Ionic Compound (salt)
– formed from electrovalent attraction of cation for anion
Created by C. Ippolito
Dec 2006
Lewis Dot Diagrams
• used to represent valence shells of atoms
– kernel – nucleus and all inner energy levels
• represented by the element’s symbol
– valence electrons
• represented by dots surrounding the symbol
• determined by the Group or Family in periodic table
Created by C. Ippolito
Dec 2006
Dot Diagrams of Atoms
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14
• Group 18
Created by C. Ippolito
Dec 2006
Dot Diagrams of Ions
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14 – no ion
• Group 18 – no ion
Created by C. Ippolito
Dec 2006
Covalent Bond
• atoms share electrons to complete valence shell
– molecular substance – atoms held together by covalent bonds
• Nonpolar Covalent Bond
– electrons are shared equally – electronegativity <1.3
• Polar Covalent Bond
– electrons are shared unequally
– electronegativity 1.3<<1.67
• Dipole
– molecule has a slightly positive side (δ+)
– molecule has a slightly negative side (δ-)
Created by C. Ippolito
Dec 2006
Nonpolar Covalent Bond
Representations
• Molecular Formula
• Dot Diagram
• Structural Formula
Created by C. Ippolito
Dec 2006
Multiple Covalent Bonds
• Single Bond
– 1 electron pair shared
• Double Bond
– 2 electron pairs shared
• Triple Bond
– 3 electron pairs shared
Created by C. Ippolito
Dec 2006
Hybridization
• rearrangement of electrons within the
valence orbitals during chemical reactions
– sp hybridization in carbon atom
• 1s22s22p2 configuration is changed in bonding
• one 2s electron is “elevated” to “equalize” all 2
orbitals
– 1s22spx1spy1spz1
Created by C. Ippolito
Dec 2006
Resonance
• explains structures that experimentally do
not conform to dot diagrams
– electrons are seen to move from one bond to
another bond and back again
– they “resonate”
Created by C. Ippolito
Dec 2006
VSEPR Modeling
• Valence Shell Electron Pair Repulsion
– used to explain shapes of molecules
– bonded atom’s electron clouds balance forces of
repulsion and attraction
– this “spaces” them apart as far as they possible
can be from each other
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Tetrahedral Shape
– bond angle 109.47o
– CH4
• Trigonal Pyramidal Shape
– bond angle 107o
– NH3
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Trigonal Planar Shape
– bond angle 120o
– SO3
• Bent Shape
– bond angle 105o
– H2O
• Linear Shape
– bond angle 180o
Created by C. Ippolito
Dec 2006
Hydrogen Bonding
• special attraction between dipoles and compounds
with hydrogen
– hydrogen atom with (δ+) slight positive charge forms
weak bond with highly electronegative atoms in other
molecules that have (δ-) slight negative charge
• special properties of water
– ice less dense than water
– high heat of vaporization (cooling property)
• holds DNA molecule halves together allowing replication
Created by C. Ippolito
Dec 2006
Metallic Bond
• metal atoms in solid and liquid state
– “positive ions” in a “sea” of free flowing
electrons
Created by C. Ippolito
Dec 2006
Network Solids
• covalent crystals
– atoms continuously bonded in a definite pattern
– “one giant” molecule
• very hard
• very high melting points
• poor conductors
Created by C. Ippolito
Dec 2006
Ionic Crystals
• ions packed in a regular pattern
– each anion is surrounded by cations
– each cation surrounded by anions
• high melting point
• nonconductive as solid
• conductive as liquid or dissolved
– because “lattice” structure is broken
Created by C. Ippolito
Dec 2006
Slide 2
Chemical Bonding
Objectives:
1.
describe the nature of a chemical bond and its relationship to
valence electrons
2.
compare ionic and covalent bonding
3.
use Lewis Dot Diagrams to represent ionic and covalent compounds
4.
describe the relationship between molecular polarity and bond
polarity
5.
explain the nature and effects of metallic bonding, hydrogen
bonding, and van der Waals forces
6.
compare the structure and properties of polar and nonpolar
molecules
7.
compare the four classes of solids: ionic, molecular, metallic, and
network
Created by C. Ippolito
Dec 2006
Chemical Bonding
• Chemical Bond
– force of attraction that holds atoms together to form
compounds
• Types of Bonds
–
–
–
–
Ionic Bond – transfer electrons – electronegativity >1.67
Covalent Bond – share electrons – electronegativity <1.67
Metallic Bond – free moving electrons in “cloud”
Network Bond – extended covalent bonds
Created by C. Ippolito
Dec 2006
Ionic Bonds
• electrons transferred from one element to another
to complete their valence shells
– Cation – positive ion loses electron – metal
– Anion – negative ion gains electron – nonmetal
• Stable Octet
– atoms gain stability by completing their valence shell
– this is done when shell is filled with eight electrons
• Ionic Compound (salt)
– formed from electrovalent attraction of cation for anion
Created by C. Ippolito
Dec 2006
Lewis Dot Diagrams
• used to represent valence shells of atoms
– kernel – nucleus and all inner energy levels
• represented by the element’s symbol
– valence electrons
• represented by dots surrounding the symbol
• determined by the Group or Family in periodic table
Created by C. Ippolito
Dec 2006
Dot Diagrams of Atoms
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14
• Group 18
Created by C. Ippolito
Dec 2006
Dot Diagrams of Ions
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14 – no ion
• Group 18 – no ion
Created by C. Ippolito
Dec 2006
Covalent Bond
• atoms share electrons to complete valence shell
– molecular substance – atoms held together by covalent bonds
• Nonpolar Covalent Bond
– electrons are shared equally – electronegativity <1.3
• Polar Covalent Bond
– electrons are shared unequally
– electronegativity 1.3<<1.67
• Dipole
– molecule has a slightly positive side (δ+)
– molecule has a slightly negative side (δ-)
Created by C. Ippolito
Dec 2006
Nonpolar Covalent Bond
Representations
• Molecular Formula
• Dot Diagram
• Structural Formula
Created by C. Ippolito
Dec 2006
Multiple Covalent Bonds
• Single Bond
– 1 electron pair shared
• Double Bond
– 2 electron pairs shared
• Triple Bond
– 3 electron pairs shared
Created by C. Ippolito
Dec 2006
Hybridization
• rearrangement of electrons within the
valence orbitals during chemical reactions
– sp hybridization in carbon atom
• 1s22s22p2 configuration is changed in bonding
• one 2s electron is “elevated” to “equalize” all 2
orbitals
– 1s22spx1spy1spz1
Created by C. Ippolito
Dec 2006
Resonance
• explains structures that experimentally do
not conform to dot diagrams
– electrons are seen to move from one bond to
another bond and back again
– they “resonate”
Created by C. Ippolito
Dec 2006
VSEPR Modeling
• Valence Shell Electron Pair Repulsion
– used to explain shapes of molecules
– bonded atom’s electron clouds balance forces of
repulsion and attraction
– this “spaces” them apart as far as they possible
can be from each other
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Tetrahedral Shape
– bond angle 109.47o
– CH4
• Trigonal Pyramidal Shape
– bond angle 107o
– NH3
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Trigonal Planar Shape
– bond angle 120o
– SO3
• Bent Shape
– bond angle 105o
– H2O
• Linear Shape
– bond angle 180o
Created by C. Ippolito
Dec 2006
Hydrogen Bonding
• special attraction between dipoles and compounds
with hydrogen
– hydrogen atom with (δ+) slight positive charge forms
weak bond with highly electronegative atoms in other
molecules that have (δ-) slight negative charge
• special properties of water
– ice less dense than water
– high heat of vaporization (cooling property)
• holds DNA molecule halves together allowing replication
Created by C. Ippolito
Dec 2006
Metallic Bond
• metal atoms in solid and liquid state
– “positive ions” in a “sea” of free flowing
electrons
Created by C. Ippolito
Dec 2006
Network Solids
• covalent crystals
– atoms continuously bonded in a definite pattern
– “one giant” molecule
• very hard
• very high melting points
• poor conductors
Created by C. Ippolito
Dec 2006
Ionic Crystals
• ions packed in a regular pattern
– each anion is surrounded by cations
– each cation surrounded by anions
• high melting point
• nonconductive as solid
• conductive as liquid or dissolved
– because “lattice” structure is broken
Created by C. Ippolito
Dec 2006
Slide 3
Chemical Bonding
Objectives:
1.
describe the nature of a chemical bond and its relationship to
valence electrons
2.
compare ionic and covalent bonding
3.
use Lewis Dot Diagrams to represent ionic and covalent compounds
4.
describe the relationship between molecular polarity and bond
polarity
5.
explain the nature and effects of metallic bonding, hydrogen
bonding, and van der Waals forces
6.
compare the structure and properties of polar and nonpolar
molecules
7.
compare the four classes of solids: ionic, molecular, metallic, and
network
Created by C. Ippolito
Dec 2006
Chemical Bonding
• Chemical Bond
– force of attraction that holds atoms together to form
compounds
• Types of Bonds
–
–
–
–
Ionic Bond – transfer electrons – electronegativity >1.67
Covalent Bond – share electrons – electronegativity <1.67
Metallic Bond – free moving electrons in “cloud”
Network Bond – extended covalent bonds
Created by C. Ippolito
Dec 2006
Ionic Bonds
• electrons transferred from one element to another
to complete their valence shells
– Cation – positive ion loses electron – metal
– Anion – negative ion gains electron – nonmetal
• Stable Octet
– atoms gain stability by completing their valence shell
– this is done when shell is filled with eight electrons
• Ionic Compound (salt)
– formed from electrovalent attraction of cation for anion
Created by C. Ippolito
Dec 2006
Lewis Dot Diagrams
• used to represent valence shells of atoms
– kernel – nucleus and all inner energy levels
• represented by the element’s symbol
– valence electrons
• represented by dots surrounding the symbol
• determined by the Group or Family in periodic table
Created by C. Ippolito
Dec 2006
Dot Diagrams of Atoms
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14
• Group 18
Created by C. Ippolito
Dec 2006
Dot Diagrams of Ions
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14 – no ion
• Group 18 – no ion
Created by C. Ippolito
Dec 2006
Covalent Bond
• atoms share electrons to complete valence shell
– molecular substance – atoms held together by covalent bonds
• Nonpolar Covalent Bond
– electrons are shared equally – electronegativity <1.3
• Polar Covalent Bond
– electrons are shared unequally
– electronegativity 1.3<<1.67
• Dipole
– molecule has a slightly positive side (δ+)
– molecule has a slightly negative side (δ-)
Created by C. Ippolito
Dec 2006
Nonpolar Covalent Bond
Representations
• Molecular Formula
• Dot Diagram
• Structural Formula
Created by C. Ippolito
Dec 2006
Multiple Covalent Bonds
• Single Bond
– 1 electron pair shared
• Double Bond
– 2 electron pairs shared
• Triple Bond
– 3 electron pairs shared
Created by C. Ippolito
Dec 2006
Hybridization
• rearrangement of electrons within the
valence orbitals during chemical reactions
– sp hybridization in carbon atom
• 1s22s22p2 configuration is changed in bonding
• one 2s electron is “elevated” to “equalize” all 2
orbitals
– 1s22spx1spy1spz1
Created by C. Ippolito
Dec 2006
Resonance
• explains structures that experimentally do
not conform to dot diagrams
– electrons are seen to move from one bond to
another bond and back again
– they “resonate”
Created by C. Ippolito
Dec 2006
VSEPR Modeling
• Valence Shell Electron Pair Repulsion
– used to explain shapes of molecules
– bonded atom’s electron clouds balance forces of
repulsion and attraction
– this “spaces” them apart as far as they possible
can be from each other
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Tetrahedral Shape
– bond angle 109.47o
– CH4
• Trigonal Pyramidal Shape
– bond angle 107o
– NH3
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Trigonal Planar Shape
– bond angle 120o
– SO3
• Bent Shape
– bond angle 105o
– H2O
• Linear Shape
– bond angle 180o
Created by C. Ippolito
Dec 2006
Hydrogen Bonding
• special attraction between dipoles and compounds
with hydrogen
– hydrogen atom with (δ+) slight positive charge forms
weak bond with highly electronegative atoms in other
molecules that have (δ-) slight negative charge
• special properties of water
– ice less dense than water
– high heat of vaporization (cooling property)
• holds DNA molecule halves together allowing replication
Created by C. Ippolito
Dec 2006
Metallic Bond
• metal atoms in solid and liquid state
– “positive ions” in a “sea” of free flowing
electrons
Created by C. Ippolito
Dec 2006
Network Solids
• covalent crystals
– atoms continuously bonded in a definite pattern
– “one giant” molecule
• very hard
• very high melting points
• poor conductors
Created by C. Ippolito
Dec 2006
Ionic Crystals
• ions packed in a regular pattern
– each anion is surrounded by cations
– each cation surrounded by anions
• high melting point
• nonconductive as solid
• conductive as liquid or dissolved
– because “lattice” structure is broken
Created by C. Ippolito
Dec 2006
Slide 4
Chemical Bonding
Objectives:
1.
describe the nature of a chemical bond and its relationship to
valence electrons
2.
compare ionic and covalent bonding
3.
use Lewis Dot Diagrams to represent ionic and covalent compounds
4.
describe the relationship between molecular polarity and bond
polarity
5.
explain the nature and effects of metallic bonding, hydrogen
bonding, and van der Waals forces
6.
compare the structure and properties of polar and nonpolar
molecules
7.
compare the four classes of solids: ionic, molecular, metallic, and
network
Created by C. Ippolito
Dec 2006
Chemical Bonding
• Chemical Bond
– force of attraction that holds atoms together to form
compounds
• Types of Bonds
–
–
–
–
Ionic Bond – transfer electrons – electronegativity >1.67
Covalent Bond – share electrons – electronegativity <1.67
Metallic Bond – free moving electrons in “cloud”
Network Bond – extended covalent bonds
Created by C. Ippolito
Dec 2006
Ionic Bonds
• electrons transferred from one element to another
to complete their valence shells
– Cation – positive ion loses electron – metal
– Anion – negative ion gains electron – nonmetal
• Stable Octet
– atoms gain stability by completing their valence shell
– this is done when shell is filled with eight electrons
• Ionic Compound (salt)
– formed from electrovalent attraction of cation for anion
Created by C. Ippolito
Dec 2006
Lewis Dot Diagrams
• used to represent valence shells of atoms
– kernel – nucleus and all inner energy levels
• represented by the element’s symbol
– valence electrons
• represented by dots surrounding the symbol
• determined by the Group or Family in periodic table
Created by C. Ippolito
Dec 2006
Dot Diagrams of Atoms
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14
• Group 18
Created by C. Ippolito
Dec 2006
Dot Diagrams of Ions
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14 – no ion
• Group 18 – no ion
Created by C. Ippolito
Dec 2006
Covalent Bond
• atoms share electrons to complete valence shell
– molecular substance – atoms held together by covalent bonds
• Nonpolar Covalent Bond
– electrons are shared equally – electronegativity <1.3
• Polar Covalent Bond
– electrons are shared unequally
– electronegativity 1.3<<1.67
• Dipole
– molecule has a slightly positive side (δ+)
– molecule has a slightly negative side (δ-)
Created by C. Ippolito
Dec 2006
Nonpolar Covalent Bond
Representations
• Molecular Formula
• Dot Diagram
• Structural Formula
Created by C. Ippolito
Dec 2006
Multiple Covalent Bonds
• Single Bond
– 1 electron pair shared
• Double Bond
– 2 electron pairs shared
• Triple Bond
– 3 electron pairs shared
Created by C. Ippolito
Dec 2006
Hybridization
• rearrangement of electrons within the
valence orbitals during chemical reactions
– sp hybridization in carbon atom
• 1s22s22p2 configuration is changed in bonding
• one 2s electron is “elevated” to “equalize” all 2
orbitals
– 1s22spx1spy1spz1
Created by C. Ippolito
Dec 2006
Resonance
• explains structures that experimentally do
not conform to dot diagrams
– electrons are seen to move from one bond to
another bond and back again
– they “resonate”
Created by C. Ippolito
Dec 2006
VSEPR Modeling
• Valence Shell Electron Pair Repulsion
– used to explain shapes of molecules
– bonded atom’s electron clouds balance forces of
repulsion and attraction
– this “spaces” them apart as far as they possible
can be from each other
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Tetrahedral Shape
– bond angle 109.47o
– CH4
• Trigonal Pyramidal Shape
– bond angle 107o
– NH3
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Trigonal Planar Shape
– bond angle 120o
– SO3
• Bent Shape
– bond angle 105o
– H2O
• Linear Shape
– bond angle 180o
Created by C. Ippolito
Dec 2006
Hydrogen Bonding
• special attraction between dipoles and compounds
with hydrogen
– hydrogen atom with (δ+) slight positive charge forms
weak bond with highly electronegative atoms in other
molecules that have (δ-) slight negative charge
• special properties of water
– ice less dense than water
– high heat of vaporization (cooling property)
• holds DNA molecule halves together allowing replication
Created by C. Ippolito
Dec 2006
Metallic Bond
• metal atoms in solid and liquid state
– “positive ions” in a “sea” of free flowing
electrons
Created by C. Ippolito
Dec 2006
Network Solids
• covalent crystals
– atoms continuously bonded in a definite pattern
– “one giant” molecule
• very hard
• very high melting points
• poor conductors
Created by C. Ippolito
Dec 2006
Ionic Crystals
• ions packed in a regular pattern
– each anion is surrounded by cations
– each cation surrounded by anions
• high melting point
• nonconductive as solid
• conductive as liquid or dissolved
– because “lattice” structure is broken
Created by C. Ippolito
Dec 2006
Slide 5
Chemical Bonding
Objectives:
1.
describe the nature of a chemical bond and its relationship to
valence electrons
2.
compare ionic and covalent bonding
3.
use Lewis Dot Diagrams to represent ionic and covalent compounds
4.
describe the relationship between molecular polarity and bond
polarity
5.
explain the nature and effects of metallic bonding, hydrogen
bonding, and van der Waals forces
6.
compare the structure and properties of polar and nonpolar
molecules
7.
compare the four classes of solids: ionic, molecular, metallic, and
network
Created by C. Ippolito
Dec 2006
Chemical Bonding
• Chemical Bond
– force of attraction that holds atoms together to form
compounds
• Types of Bonds
–
–
–
–
Ionic Bond – transfer electrons – electronegativity >1.67
Covalent Bond – share electrons – electronegativity <1.67
Metallic Bond – free moving electrons in “cloud”
Network Bond – extended covalent bonds
Created by C. Ippolito
Dec 2006
Ionic Bonds
• electrons transferred from one element to another
to complete their valence shells
– Cation – positive ion loses electron – metal
– Anion – negative ion gains electron – nonmetal
• Stable Octet
– atoms gain stability by completing their valence shell
– this is done when shell is filled with eight electrons
• Ionic Compound (salt)
– formed from electrovalent attraction of cation for anion
Created by C. Ippolito
Dec 2006
Lewis Dot Diagrams
• used to represent valence shells of atoms
– kernel – nucleus and all inner energy levels
• represented by the element’s symbol
– valence electrons
• represented by dots surrounding the symbol
• determined by the Group or Family in periodic table
Created by C. Ippolito
Dec 2006
Dot Diagrams of Atoms
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14
• Group 18
Created by C. Ippolito
Dec 2006
Dot Diagrams of Ions
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14 – no ion
• Group 18 – no ion
Created by C. Ippolito
Dec 2006
Covalent Bond
• atoms share electrons to complete valence shell
– molecular substance – atoms held together by covalent bonds
• Nonpolar Covalent Bond
– electrons are shared equally – electronegativity <1.3
• Polar Covalent Bond
– electrons are shared unequally
– electronegativity 1.3<<1.67
• Dipole
– molecule has a slightly positive side (δ+)
– molecule has a slightly negative side (δ-)
Created by C. Ippolito
Dec 2006
Nonpolar Covalent Bond
Representations
• Molecular Formula
• Dot Diagram
• Structural Formula
Created by C. Ippolito
Dec 2006
Multiple Covalent Bonds
• Single Bond
– 1 electron pair shared
• Double Bond
– 2 electron pairs shared
• Triple Bond
– 3 electron pairs shared
Created by C. Ippolito
Dec 2006
Hybridization
• rearrangement of electrons within the
valence orbitals during chemical reactions
– sp hybridization in carbon atom
• 1s22s22p2 configuration is changed in bonding
• one 2s electron is “elevated” to “equalize” all 2
orbitals
– 1s22spx1spy1spz1
Created by C. Ippolito
Dec 2006
Resonance
• explains structures that experimentally do
not conform to dot diagrams
– electrons are seen to move from one bond to
another bond and back again
– they “resonate”
Created by C. Ippolito
Dec 2006
VSEPR Modeling
• Valence Shell Electron Pair Repulsion
– used to explain shapes of molecules
– bonded atom’s electron clouds balance forces of
repulsion and attraction
– this “spaces” them apart as far as they possible
can be from each other
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Tetrahedral Shape
– bond angle 109.47o
– CH4
• Trigonal Pyramidal Shape
– bond angle 107o
– NH3
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Trigonal Planar Shape
– bond angle 120o
– SO3
• Bent Shape
– bond angle 105o
– H2O
• Linear Shape
– bond angle 180o
Created by C. Ippolito
Dec 2006
Hydrogen Bonding
• special attraction between dipoles and compounds
with hydrogen
– hydrogen atom with (δ+) slight positive charge forms
weak bond with highly electronegative atoms in other
molecules that have (δ-) slight negative charge
• special properties of water
– ice less dense than water
– high heat of vaporization (cooling property)
• holds DNA molecule halves together allowing replication
Created by C. Ippolito
Dec 2006
Metallic Bond
• metal atoms in solid and liquid state
– “positive ions” in a “sea” of free flowing
electrons
Created by C. Ippolito
Dec 2006
Network Solids
• covalent crystals
– atoms continuously bonded in a definite pattern
– “one giant” molecule
• very hard
• very high melting points
• poor conductors
Created by C. Ippolito
Dec 2006
Ionic Crystals
• ions packed in a regular pattern
– each anion is surrounded by cations
– each cation surrounded by anions
• high melting point
• nonconductive as solid
• conductive as liquid or dissolved
– because “lattice” structure is broken
Created by C. Ippolito
Dec 2006
Slide 6
Chemical Bonding
Objectives:
1.
describe the nature of a chemical bond and its relationship to
valence electrons
2.
compare ionic and covalent bonding
3.
use Lewis Dot Diagrams to represent ionic and covalent compounds
4.
describe the relationship between molecular polarity and bond
polarity
5.
explain the nature and effects of metallic bonding, hydrogen
bonding, and van der Waals forces
6.
compare the structure and properties of polar and nonpolar
molecules
7.
compare the four classes of solids: ionic, molecular, metallic, and
network
Created by C. Ippolito
Dec 2006
Chemical Bonding
• Chemical Bond
– force of attraction that holds atoms together to form
compounds
• Types of Bonds
–
–
–
–
Ionic Bond – transfer electrons – electronegativity >1.67
Covalent Bond – share electrons – electronegativity <1.67
Metallic Bond – free moving electrons in “cloud”
Network Bond – extended covalent bonds
Created by C. Ippolito
Dec 2006
Ionic Bonds
• electrons transferred from one element to another
to complete their valence shells
– Cation – positive ion loses electron – metal
– Anion – negative ion gains electron – nonmetal
• Stable Octet
– atoms gain stability by completing their valence shell
– this is done when shell is filled with eight electrons
• Ionic Compound (salt)
– formed from electrovalent attraction of cation for anion
Created by C. Ippolito
Dec 2006
Lewis Dot Diagrams
• used to represent valence shells of atoms
– kernel – nucleus and all inner energy levels
• represented by the element’s symbol
– valence electrons
• represented by dots surrounding the symbol
• determined by the Group or Family in periodic table
Created by C. Ippolito
Dec 2006
Dot Diagrams of Atoms
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14
• Group 18
Created by C. Ippolito
Dec 2006
Dot Diagrams of Ions
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14 – no ion
• Group 18 – no ion
Created by C. Ippolito
Dec 2006
Covalent Bond
• atoms share electrons to complete valence shell
– molecular substance – atoms held together by covalent bonds
• Nonpolar Covalent Bond
– electrons are shared equally – electronegativity <1.3
• Polar Covalent Bond
– electrons are shared unequally
– electronegativity 1.3<<1.67
• Dipole
– molecule has a slightly positive side (δ+)
– molecule has a slightly negative side (δ-)
Created by C. Ippolito
Dec 2006
Nonpolar Covalent Bond
Representations
• Molecular Formula
• Dot Diagram
• Structural Formula
Created by C. Ippolito
Dec 2006
Multiple Covalent Bonds
• Single Bond
– 1 electron pair shared
• Double Bond
– 2 electron pairs shared
• Triple Bond
– 3 electron pairs shared
Created by C. Ippolito
Dec 2006
Hybridization
• rearrangement of electrons within the
valence orbitals during chemical reactions
– sp hybridization in carbon atom
• 1s22s22p2 configuration is changed in bonding
• one 2s electron is “elevated” to “equalize” all 2
orbitals
– 1s22spx1spy1spz1
Created by C. Ippolito
Dec 2006
Resonance
• explains structures that experimentally do
not conform to dot diagrams
– electrons are seen to move from one bond to
another bond and back again
– they “resonate”
Created by C. Ippolito
Dec 2006
VSEPR Modeling
• Valence Shell Electron Pair Repulsion
– used to explain shapes of molecules
– bonded atom’s electron clouds balance forces of
repulsion and attraction
– this “spaces” them apart as far as they possible
can be from each other
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Tetrahedral Shape
– bond angle 109.47o
– CH4
• Trigonal Pyramidal Shape
– bond angle 107o
– NH3
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Trigonal Planar Shape
– bond angle 120o
– SO3
• Bent Shape
– bond angle 105o
– H2O
• Linear Shape
– bond angle 180o
Created by C. Ippolito
Dec 2006
Hydrogen Bonding
• special attraction between dipoles and compounds
with hydrogen
– hydrogen atom with (δ+) slight positive charge forms
weak bond with highly electronegative atoms in other
molecules that have (δ-) slight negative charge
• special properties of water
– ice less dense than water
– high heat of vaporization (cooling property)
• holds DNA molecule halves together allowing replication
Created by C. Ippolito
Dec 2006
Metallic Bond
• metal atoms in solid and liquid state
– “positive ions” in a “sea” of free flowing
electrons
Created by C. Ippolito
Dec 2006
Network Solids
• covalent crystals
– atoms continuously bonded in a definite pattern
– “one giant” molecule
• very hard
• very high melting points
• poor conductors
Created by C. Ippolito
Dec 2006
Ionic Crystals
• ions packed in a regular pattern
– each anion is surrounded by cations
– each cation surrounded by anions
• high melting point
• nonconductive as solid
• conductive as liquid or dissolved
– because “lattice” structure is broken
Created by C. Ippolito
Dec 2006
Slide 7
Chemical Bonding
Objectives:
1.
describe the nature of a chemical bond and its relationship to
valence electrons
2.
compare ionic and covalent bonding
3.
use Lewis Dot Diagrams to represent ionic and covalent compounds
4.
describe the relationship between molecular polarity and bond
polarity
5.
explain the nature and effects of metallic bonding, hydrogen
bonding, and van der Waals forces
6.
compare the structure and properties of polar and nonpolar
molecules
7.
compare the four classes of solids: ionic, molecular, metallic, and
network
Created by C. Ippolito
Dec 2006
Chemical Bonding
• Chemical Bond
– force of attraction that holds atoms together to form
compounds
• Types of Bonds
–
–
–
–
Ionic Bond – transfer electrons – electronegativity >1.67
Covalent Bond – share electrons – electronegativity <1.67
Metallic Bond – free moving electrons in “cloud”
Network Bond – extended covalent bonds
Created by C. Ippolito
Dec 2006
Ionic Bonds
• electrons transferred from one element to another
to complete their valence shells
– Cation – positive ion loses electron – metal
– Anion – negative ion gains electron – nonmetal
• Stable Octet
– atoms gain stability by completing their valence shell
– this is done when shell is filled with eight electrons
• Ionic Compound (salt)
– formed from electrovalent attraction of cation for anion
Created by C. Ippolito
Dec 2006
Lewis Dot Diagrams
• used to represent valence shells of atoms
– kernel – nucleus and all inner energy levels
• represented by the element’s symbol
– valence electrons
• represented by dots surrounding the symbol
• determined by the Group or Family in periodic table
Created by C. Ippolito
Dec 2006
Dot Diagrams of Atoms
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14
• Group 18
Created by C. Ippolito
Dec 2006
Dot Diagrams of Ions
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14 – no ion
• Group 18 – no ion
Created by C. Ippolito
Dec 2006
Covalent Bond
• atoms share electrons to complete valence shell
– molecular substance – atoms held together by covalent bonds
• Nonpolar Covalent Bond
– electrons are shared equally – electronegativity <1.3
• Polar Covalent Bond
– electrons are shared unequally
– electronegativity 1.3<<1.67
• Dipole
– molecule has a slightly positive side (δ+)
– molecule has a slightly negative side (δ-)
Created by C. Ippolito
Dec 2006
Nonpolar Covalent Bond
Representations
• Molecular Formula
• Dot Diagram
• Structural Formula
Created by C. Ippolito
Dec 2006
Multiple Covalent Bonds
• Single Bond
– 1 electron pair shared
• Double Bond
– 2 electron pairs shared
• Triple Bond
– 3 electron pairs shared
Created by C. Ippolito
Dec 2006
Hybridization
• rearrangement of electrons within the
valence orbitals during chemical reactions
– sp hybridization in carbon atom
• 1s22s22p2 configuration is changed in bonding
• one 2s electron is “elevated” to “equalize” all 2
orbitals
– 1s22spx1spy1spz1
Created by C. Ippolito
Dec 2006
Resonance
• explains structures that experimentally do
not conform to dot diagrams
– electrons are seen to move from one bond to
another bond and back again
– they “resonate”
Created by C. Ippolito
Dec 2006
VSEPR Modeling
• Valence Shell Electron Pair Repulsion
– used to explain shapes of molecules
– bonded atom’s electron clouds balance forces of
repulsion and attraction
– this “spaces” them apart as far as they possible
can be from each other
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Tetrahedral Shape
– bond angle 109.47o
– CH4
• Trigonal Pyramidal Shape
– bond angle 107o
– NH3
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Trigonal Planar Shape
– bond angle 120o
– SO3
• Bent Shape
– bond angle 105o
– H2O
• Linear Shape
– bond angle 180o
Created by C. Ippolito
Dec 2006
Hydrogen Bonding
• special attraction between dipoles and compounds
with hydrogen
– hydrogen atom with (δ+) slight positive charge forms
weak bond with highly electronegative atoms in other
molecules that have (δ-) slight negative charge
• special properties of water
– ice less dense than water
– high heat of vaporization (cooling property)
• holds DNA molecule halves together allowing replication
Created by C. Ippolito
Dec 2006
Metallic Bond
• metal atoms in solid and liquid state
– “positive ions” in a “sea” of free flowing
electrons
Created by C. Ippolito
Dec 2006
Network Solids
• covalent crystals
– atoms continuously bonded in a definite pattern
– “one giant” molecule
• very hard
• very high melting points
• poor conductors
Created by C. Ippolito
Dec 2006
Ionic Crystals
• ions packed in a regular pattern
– each anion is surrounded by cations
– each cation surrounded by anions
• high melting point
• nonconductive as solid
• conductive as liquid or dissolved
– because “lattice” structure is broken
Created by C. Ippolito
Dec 2006
Slide 8
Chemical Bonding
Objectives:
1.
describe the nature of a chemical bond and its relationship to
valence electrons
2.
compare ionic and covalent bonding
3.
use Lewis Dot Diagrams to represent ionic and covalent compounds
4.
describe the relationship between molecular polarity and bond
polarity
5.
explain the nature and effects of metallic bonding, hydrogen
bonding, and van der Waals forces
6.
compare the structure and properties of polar and nonpolar
molecules
7.
compare the four classes of solids: ionic, molecular, metallic, and
network
Created by C. Ippolito
Dec 2006
Chemical Bonding
• Chemical Bond
– force of attraction that holds atoms together to form
compounds
• Types of Bonds
–
–
–
–
Ionic Bond – transfer electrons – electronegativity >1.67
Covalent Bond – share electrons – electronegativity <1.67
Metallic Bond – free moving electrons in “cloud”
Network Bond – extended covalent bonds
Created by C. Ippolito
Dec 2006
Ionic Bonds
• electrons transferred from one element to another
to complete their valence shells
– Cation – positive ion loses electron – metal
– Anion – negative ion gains electron – nonmetal
• Stable Octet
– atoms gain stability by completing their valence shell
– this is done when shell is filled with eight electrons
• Ionic Compound (salt)
– formed from electrovalent attraction of cation for anion
Created by C. Ippolito
Dec 2006
Lewis Dot Diagrams
• used to represent valence shells of atoms
– kernel – nucleus and all inner energy levels
• represented by the element’s symbol
– valence electrons
• represented by dots surrounding the symbol
• determined by the Group or Family in periodic table
Created by C. Ippolito
Dec 2006
Dot Diagrams of Atoms
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14
• Group 18
Created by C. Ippolito
Dec 2006
Dot Diagrams of Ions
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14 – no ion
• Group 18 – no ion
Created by C. Ippolito
Dec 2006
Covalent Bond
• atoms share electrons to complete valence shell
– molecular substance – atoms held together by covalent bonds
• Nonpolar Covalent Bond
– electrons are shared equally – electronegativity <1.3
• Polar Covalent Bond
– electrons are shared unequally
– electronegativity 1.3<<1.67
• Dipole
– molecule has a slightly positive side (δ+)
– molecule has a slightly negative side (δ-)
Created by C. Ippolito
Dec 2006
Nonpolar Covalent Bond
Representations
• Molecular Formula
• Dot Diagram
• Structural Formula
Created by C. Ippolito
Dec 2006
Multiple Covalent Bonds
• Single Bond
– 1 electron pair shared
• Double Bond
– 2 electron pairs shared
• Triple Bond
– 3 electron pairs shared
Created by C. Ippolito
Dec 2006
Hybridization
• rearrangement of electrons within the
valence orbitals during chemical reactions
– sp hybridization in carbon atom
• 1s22s22p2 configuration is changed in bonding
• one 2s electron is “elevated” to “equalize” all 2
orbitals
– 1s22spx1spy1spz1
Created by C. Ippolito
Dec 2006
Resonance
• explains structures that experimentally do
not conform to dot diagrams
– electrons are seen to move from one bond to
another bond and back again
– they “resonate”
Created by C. Ippolito
Dec 2006
VSEPR Modeling
• Valence Shell Electron Pair Repulsion
– used to explain shapes of molecules
– bonded atom’s electron clouds balance forces of
repulsion and attraction
– this “spaces” them apart as far as they possible
can be from each other
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Tetrahedral Shape
– bond angle 109.47o
– CH4
• Trigonal Pyramidal Shape
– bond angle 107o
– NH3
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Trigonal Planar Shape
– bond angle 120o
– SO3
• Bent Shape
– bond angle 105o
– H2O
• Linear Shape
– bond angle 180o
Created by C. Ippolito
Dec 2006
Hydrogen Bonding
• special attraction between dipoles and compounds
with hydrogen
– hydrogen atom with (δ+) slight positive charge forms
weak bond with highly electronegative atoms in other
molecules that have (δ-) slight negative charge
• special properties of water
– ice less dense than water
– high heat of vaporization (cooling property)
• holds DNA molecule halves together allowing replication
Created by C. Ippolito
Dec 2006
Metallic Bond
• metal atoms in solid and liquid state
– “positive ions” in a “sea” of free flowing
electrons
Created by C. Ippolito
Dec 2006
Network Solids
• covalent crystals
– atoms continuously bonded in a definite pattern
– “one giant” molecule
• very hard
• very high melting points
• poor conductors
Created by C. Ippolito
Dec 2006
Ionic Crystals
• ions packed in a regular pattern
– each anion is surrounded by cations
– each cation surrounded by anions
• high melting point
• nonconductive as solid
• conductive as liquid or dissolved
– because “lattice” structure is broken
Created by C. Ippolito
Dec 2006
Slide 9
Chemical Bonding
Objectives:
1.
describe the nature of a chemical bond and its relationship to
valence electrons
2.
compare ionic and covalent bonding
3.
use Lewis Dot Diagrams to represent ionic and covalent compounds
4.
describe the relationship between molecular polarity and bond
polarity
5.
explain the nature and effects of metallic bonding, hydrogen
bonding, and van der Waals forces
6.
compare the structure and properties of polar and nonpolar
molecules
7.
compare the four classes of solids: ionic, molecular, metallic, and
network
Created by C. Ippolito
Dec 2006
Chemical Bonding
• Chemical Bond
– force of attraction that holds atoms together to form
compounds
• Types of Bonds
–
–
–
–
Ionic Bond – transfer electrons – electronegativity >1.67
Covalent Bond – share electrons – electronegativity <1.67
Metallic Bond – free moving electrons in “cloud”
Network Bond – extended covalent bonds
Created by C. Ippolito
Dec 2006
Ionic Bonds
• electrons transferred from one element to another
to complete their valence shells
– Cation – positive ion loses electron – metal
– Anion – negative ion gains electron – nonmetal
• Stable Octet
– atoms gain stability by completing their valence shell
– this is done when shell is filled with eight electrons
• Ionic Compound (salt)
– formed from electrovalent attraction of cation for anion
Created by C. Ippolito
Dec 2006
Lewis Dot Diagrams
• used to represent valence shells of atoms
– kernel – nucleus and all inner energy levels
• represented by the element’s symbol
– valence electrons
• represented by dots surrounding the symbol
• determined by the Group or Family in periodic table
Created by C. Ippolito
Dec 2006
Dot Diagrams of Atoms
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14
• Group 18
Created by C. Ippolito
Dec 2006
Dot Diagrams of Ions
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14 – no ion
• Group 18 – no ion
Created by C. Ippolito
Dec 2006
Covalent Bond
• atoms share electrons to complete valence shell
– molecular substance – atoms held together by covalent bonds
• Nonpolar Covalent Bond
– electrons are shared equally – electronegativity <1.3
• Polar Covalent Bond
– electrons are shared unequally
– electronegativity 1.3<<1.67
• Dipole
– molecule has a slightly positive side (δ+)
– molecule has a slightly negative side (δ-)
Created by C. Ippolito
Dec 2006
Nonpolar Covalent Bond
Representations
• Molecular Formula
• Dot Diagram
• Structural Formula
Created by C. Ippolito
Dec 2006
Multiple Covalent Bonds
• Single Bond
– 1 electron pair shared
• Double Bond
– 2 electron pairs shared
• Triple Bond
– 3 electron pairs shared
Created by C. Ippolito
Dec 2006
Hybridization
• rearrangement of electrons within the
valence orbitals during chemical reactions
– sp hybridization in carbon atom
• 1s22s22p2 configuration is changed in bonding
• one 2s electron is “elevated” to “equalize” all 2
orbitals
– 1s22spx1spy1spz1
Created by C. Ippolito
Dec 2006
Resonance
• explains structures that experimentally do
not conform to dot diagrams
– electrons are seen to move from one bond to
another bond and back again
– they “resonate”
Created by C. Ippolito
Dec 2006
VSEPR Modeling
• Valence Shell Electron Pair Repulsion
– used to explain shapes of molecules
– bonded atom’s electron clouds balance forces of
repulsion and attraction
– this “spaces” them apart as far as they possible
can be from each other
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Tetrahedral Shape
– bond angle 109.47o
– CH4
• Trigonal Pyramidal Shape
– bond angle 107o
– NH3
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Trigonal Planar Shape
– bond angle 120o
– SO3
• Bent Shape
– bond angle 105o
– H2O
• Linear Shape
– bond angle 180o
Created by C. Ippolito
Dec 2006
Hydrogen Bonding
• special attraction between dipoles and compounds
with hydrogen
– hydrogen atom with (δ+) slight positive charge forms
weak bond with highly electronegative atoms in other
molecules that have (δ-) slight negative charge
• special properties of water
– ice less dense than water
– high heat of vaporization (cooling property)
• holds DNA molecule halves together allowing replication
Created by C. Ippolito
Dec 2006
Metallic Bond
• metal atoms in solid and liquid state
– “positive ions” in a “sea” of free flowing
electrons
Created by C. Ippolito
Dec 2006
Network Solids
• covalent crystals
– atoms continuously bonded in a definite pattern
– “one giant” molecule
• very hard
• very high melting points
• poor conductors
Created by C. Ippolito
Dec 2006
Ionic Crystals
• ions packed in a regular pattern
– each anion is surrounded by cations
– each cation surrounded by anions
• high melting point
• nonconductive as solid
• conductive as liquid or dissolved
– because “lattice” structure is broken
Created by C. Ippolito
Dec 2006
Slide 10
Chemical Bonding
Objectives:
1.
describe the nature of a chemical bond and its relationship to
valence electrons
2.
compare ionic and covalent bonding
3.
use Lewis Dot Diagrams to represent ionic and covalent compounds
4.
describe the relationship between molecular polarity and bond
polarity
5.
explain the nature and effects of metallic bonding, hydrogen
bonding, and van der Waals forces
6.
compare the structure and properties of polar and nonpolar
molecules
7.
compare the four classes of solids: ionic, molecular, metallic, and
network
Created by C. Ippolito
Dec 2006
Chemical Bonding
• Chemical Bond
– force of attraction that holds atoms together to form
compounds
• Types of Bonds
–
–
–
–
Ionic Bond – transfer electrons – electronegativity >1.67
Covalent Bond – share electrons – electronegativity <1.67
Metallic Bond – free moving electrons in “cloud”
Network Bond – extended covalent bonds
Created by C. Ippolito
Dec 2006
Ionic Bonds
• electrons transferred from one element to another
to complete their valence shells
– Cation – positive ion loses electron – metal
– Anion – negative ion gains electron – nonmetal
• Stable Octet
– atoms gain stability by completing their valence shell
– this is done when shell is filled with eight electrons
• Ionic Compound (salt)
– formed from electrovalent attraction of cation for anion
Created by C. Ippolito
Dec 2006
Lewis Dot Diagrams
• used to represent valence shells of atoms
– kernel – nucleus and all inner energy levels
• represented by the element’s symbol
– valence electrons
• represented by dots surrounding the symbol
• determined by the Group or Family in periodic table
Created by C. Ippolito
Dec 2006
Dot Diagrams of Atoms
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14
• Group 18
Created by C. Ippolito
Dec 2006
Dot Diagrams of Ions
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14 – no ion
• Group 18 – no ion
Created by C. Ippolito
Dec 2006
Covalent Bond
• atoms share electrons to complete valence shell
– molecular substance – atoms held together by covalent bonds
• Nonpolar Covalent Bond
– electrons are shared equally – electronegativity <1.3
• Polar Covalent Bond
– electrons are shared unequally
– electronegativity 1.3<<1.67
• Dipole
– molecule has a slightly positive side (δ+)
– molecule has a slightly negative side (δ-)
Created by C. Ippolito
Dec 2006
Nonpolar Covalent Bond
Representations
• Molecular Formula
• Dot Diagram
• Structural Formula
Created by C. Ippolito
Dec 2006
Multiple Covalent Bonds
• Single Bond
– 1 electron pair shared
• Double Bond
– 2 electron pairs shared
• Triple Bond
– 3 electron pairs shared
Created by C. Ippolito
Dec 2006
Hybridization
• rearrangement of electrons within the
valence orbitals during chemical reactions
– sp hybridization in carbon atom
• 1s22s22p2 configuration is changed in bonding
• one 2s electron is “elevated” to “equalize” all 2
orbitals
– 1s22spx1spy1spz1
Created by C. Ippolito
Dec 2006
Resonance
• explains structures that experimentally do
not conform to dot diagrams
– electrons are seen to move from one bond to
another bond and back again
– they “resonate”
Created by C. Ippolito
Dec 2006
VSEPR Modeling
• Valence Shell Electron Pair Repulsion
– used to explain shapes of molecules
– bonded atom’s electron clouds balance forces of
repulsion and attraction
– this “spaces” them apart as far as they possible
can be from each other
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Tetrahedral Shape
– bond angle 109.47o
– CH4
• Trigonal Pyramidal Shape
– bond angle 107o
– NH3
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Trigonal Planar Shape
– bond angle 120o
– SO3
• Bent Shape
– bond angle 105o
– H2O
• Linear Shape
– bond angle 180o
Created by C. Ippolito
Dec 2006
Hydrogen Bonding
• special attraction between dipoles and compounds
with hydrogen
– hydrogen atom with (δ+) slight positive charge forms
weak bond with highly electronegative atoms in other
molecules that have (δ-) slight negative charge
• special properties of water
– ice less dense than water
– high heat of vaporization (cooling property)
• holds DNA molecule halves together allowing replication
Created by C. Ippolito
Dec 2006
Metallic Bond
• metal atoms in solid and liquid state
– “positive ions” in a “sea” of free flowing
electrons
Created by C. Ippolito
Dec 2006
Network Solids
• covalent crystals
– atoms continuously bonded in a definite pattern
– “one giant” molecule
• very hard
• very high melting points
• poor conductors
Created by C. Ippolito
Dec 2006
Ionic Crystals
• ions packed in a regular pattern
– each anion is surrounded by cations
– each cation surrounded by anions
• high melting point
• nonconductive as solid
• conductive as liquid or dissolved
– because “lattice” structure is broken
Created by C. Ippolito
Dec 2006
Slide 11
Chemical Bonding
Objectives:
1.
describe the nature of a chemical bond and its relationship to
valence electrons
2.
compare ionic and covalent bonding
3.
use Lewis Dot Diagrams to represent ionic and covalent compounds
4.
describe the relationship between molecular polarity and bond
polarity
5.
explain the nature and effects of metallic bonding, hydrogen
bonding, and van der Waals forces
6.
compare the structure and properties of polar and nonpolar
molecules
7.
compare the four classes of solids: ionic, molecular, metallic, and
network
Created by C. Ippolito
Dec 2006
Chemical Bonding
• Chemical Bond
– force of attraction that holds atoms together to form
compounds
• Types of Bonds
–
–
–
–
Ionic Bond – transfer electrons – electronegativity >1.67
Covalent Bond – share electrons – electronegativity <1.67
Metallic Bond – free moving electrons in “cloud”
Network Bond – extended covalent bonds
Created by C. Ippolito
Dec 2006
Ionic Bonds
• electrons transferred from one element to another
to complete their valence shells
– Cation – positive ion loses electron – metal
– Anion – negative ion gains electron – nonmetal
• Stable Octet
– atoms gain stability by completing their valence shell
– this is done when shell is filled with eight electrons
• Ionic Compound (salt)
– formed from electrovalent attraction of cation for anion
Created by C. Ippolito
Dec 2006
Lewis Dot Diagrams
• used to represent valence shells of atoms
– kernel – nucleus and all inner energy levels
• represented by the element’s symbol
– valence electrons
• represented by dots surrounding the symbol
• determined by the Group or Family in periodic table
Created by C. Ippolito
Dec 2006
Dot Diagrams of Atoms
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14
• Group 18
Created by C. Ippolito
Dec 2006
Dot Diagrams of Ions
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14 – no ion
• Group 18 – no ion
Created by C. Ippolito
Dec 2006
Covalent Bond
• atoms share electrons to complete valence shell
– molecular substance – atoms held together by covalent bonds
• Nonpolar Covalent Bond
– electrons are shared equally – electronegativity <1.3
• Polar Covalent Bond
– electrons are shared unequally
– electronegativity 1.3<<1.67
• Dipole
– molecule has a slightly positive side (δ+)
– molecule has a slightly negative side (δ-)
Created by C. Ippolito
Dec 2006
Nonpolar Covalent Bond
Representations
• Molecular Formula
• Dot Diagram
• Structural Formula
Created by C. Ippolito
Dec 2006
Multiple Covalent Bonds
• Single Bond
– 1 electron pair shared
• Double Bond
– 2 electron pairs shared
• Triple Bond
– 3 electron pairs shared
Created by C. Ippolito
Dec 2006
Hybridization
• rearrangement of electrons within the
valence orbitals during chemical reactions
– sp hybridization in carbon atom
• 1s22s22p2 configuration is changed in bonding
• one 2s electron is “elevated” to “equalize” all 2
orbitals
– 1s22spx1spy1spz1
Created by C. Ippolito
Dec 2006
Resonance
• explains structures that experimentally do
not conform to dot diagrams
– electrons are seen to move from one bond to
another bond and back again
– they “resonate”
Created by C. Ippolito
Dec 2006
VSEPR Modeling
• Valence Shell Electron Pair Repulsion
– used to explain shapes of molecules
– bonded atom’s electron clouds balance forces of
repulsion and attraction
– this “spaces” them apart as far as they possible
can be from each other
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Tetrahedral Shape
– bond angle 109.47o
– CH4
• Trigonal Pyramidal Shape
– bond angle 107o
– NH3
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Trigonal Planar Shape
– bond angle 120o
– SO3
• Bent Shape
– bond angle 105o
– H2O
• Linear Shape
– bond angle 180o
Created by C. Ippolito
Dec 2006
Hydrogen Bonding
• special attraction between dipoles and compounds
with hydrogen
– hydrogen atom with (δ+) slight positive charge forms
weak bond with highly electronegative atoms in other
molecules that have (δ-) slight negative charge
• special properties of water
– ice less dense than water
– high heat of vaporization (cooling property)
• holds DNA molecule halves together allowing replication
Created by C. Ippolito
Dec 2006
Metallic Bond
• metal atoms in solid and liquid state
– “positive ions” in a “sea” of free flowing
electrons
Created by C. Ippolito
Dec 2006
Network Solids
• covalent crystals
– atoms continuously bonded in a definite pattern
– “one giant” molecule
• very hard
• very high melting points
• poor conductors
Created by C. Ippolito
Dec 2006
Ionic Crystals
• ions packed in a regular pattern
– each anion is surrounded by cations
– each cation surrounded by anions
• high melting point
• nonconductive as solid
• conductive as liquid or dissolved
– because “lattice” structure is broken
Created by C. Ippolito
Dec 2006
Slide 12
Chemical Bonding
Objectives:
1.
describe the nature of a chemical bond and its relationship to
valence electrons
2.
compare ionic and covalent bonding
3.
use Lewis Dot Diagrams to represent ionic and covalent compounds
4.
describe the relationship between molecular polarity and bond
polarity
5.
explain the nature and effects of metallic bonding, hydrogen
bonding, and van der Waals forces
6.
compare the structure and properties of polar and nonpolar
molecules
7.
compare the four classes of solids: ionic, molecular, metallic, and
network
Created by C. Ippolito
Dec 2006
Chemical Bonding
• Chemical Bond
– force of attraction that holds atoms together to form
compounds
• Types of Bonds
–
–
–
–
Ionic Bond – transfer electrons – electronegativity >1.67
Covalent Bond – share electrons – electronegativity <1.67
Metallic Bond – free moving electrons in “cloud”
Network Bond – extended covalent bonds
Created by C. Ippolito
Dec 2006
Ionic Bonds
• electrons transferred from one element to another
to complete their valence shells
– Cation – positive ion loses electron – metal
– Anion – negative ion gains electron – nonmetal
• Stable Octet
– atoms gain stability by completing their valence shell
– this is done when shell is filled with eight electrons
• Ionic Compound (salt)
– formed from electrovalent attraction of cation for anion
Created by C. Ippolito
Dec 2006
Lewis Dot Diagrams
• used to represent valence shells of atoms
– kernel – nucleus and all inner energy levels
• represented by the element’s symbol
– valence electrons
• represented by dots surrounding the symbol
• determined by the Group or Family in periodic table
Created by C. Ippolito
Dec 2006
Dot Diagrams of Atoms
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14
• Group 18
Created by C. Ippolito
Dec 2006
Dot Diagrams of Ions
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14 – no ion
• Group 18 – no ion
Created by C. Ippolito
Dec 2006
Covalent Bond
• atoms share electrons to complete valence shell
– molecular substance – atoms held together by covalent bonds
• Nonpolar Covalent Bond
– electrons are shared equally – electronegativity <1.3
• Polar Covalent Bond
– electrons are shared unequally
– electronegativity 1.3<<1.67
• Dipole
– molecule has a slightly positive side (δ+)
– molecule has a slightly negative side (δ-)
Created by C. Ippolito
Dec 2006
Nonpolar Covalent Bond
Representations
• Molecular Formula
• Dot Diagram
• Structural Formula
Created by C. Ippolito
Dec 2006
Multiple Covalent Bonds
• Single Bond
– 1 electron pair shared
• Double Bond
– 2 electron pairs shared
• Triple Bond
– 3 electron pairs shared
Created by C. Ippolito
Dec 2006
Hybridization
• rearrangement of electrons within the
valence orbitals during chemical reactions
– sp hybridization in carbon atom
• 1s22s22p2 configuration is changed in bonding
• one 2s electron is “elevated” to “equalize” all 2
orbitals
– 1s22spx1spy1spz1
Created by C. Ippolito
Dec 2006
Resonance
• explains structures that experimentally do
not conform to dot diagrams
– electrons are seen to move from one bond to
another bond and back again
– they “resonate”
Created by C. Ippolito
Dec 2006
VSEPR Modeling
• Valence Shell Electron Pair Repulsion
– used to explain shapes of molecules
– bonded atom’s electron clouds balance forces of
repulsion and attraction
– this “spaces” them apart as far as they possible
can be from each other
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Tetrahedral Shape
– bond angle 109.47o
– CH4
• Trigonal Pyramidal Shape
– bond angle 107o
– NH3
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Trigonal Planar Shape
– bond angle 120o
– SO3
• Bent Shape
– bond angle 105o
– H2O
• Linear Shape
– bond angle 180o
Created by C. Ippolito
Dec 2006
Hydrogen Bonding
• special attraction between dipoles and compounds
with hydrogen
– hydrogen atom with (δ+) slight positive charge forms
weak bond with highly electronegative atoms in other
molecules that have (δ-) slight negative charge
• special properties of water
– ice less dense than water
– high heat of vaporization (cooling property)
• holds DNA molecule halves together allowing replication
Created by C. Ippolito
Dec 2006
Metallic Bond
• metal atoms in solid and liquid state
– “positive ions” in a “sea” of free flowing
electrons
Created by C. Ippolito
Dec 2006
Network Solids
• covalent crystals
– atoms continuously bonded in a definite pattern
– “one giant” molecule
• very hard
• very high melting points
• poor conductors
Created by C. Ippolito
Dec 2006
Ionic Crystals
• ions packed in a regular pattern
– each anion is surrounded by cations
– each cation surrounded by anions
• high melting point
• nonconductive as solid
• conductive as liquid or dissolved
– because “lattice” structure is broken
Created by C. Ippolito
Dec 2006
Slide 13
Chemical Bonding
Objectives:
1.
describe the nature of a chemical bond and its relationship to
valence electrons
2.
compare ionic and covalent bonding
3.
use Lewis Dot Diagrams to represent ionic and covalent compounds
4.
describe the relationship between molecular polarity and bond
polarity
5.
explain the nature and effects of metallic bonding, hydrogen
bonding, and van der Waals forces
6.
compare the structure and properties of polar and nonpolar
molecules
7.
compare the four classes of solids: ionic, molecular, metallic, and
network
Created by C. Ippolito
Dec 2006
Chemical Bonding
• Chemical Bond
– force of attraction that holds atoms together to form
compounds
• Types of Bonds
–
–
–
–
Ionic Bond – transfer electrons – electronegativity >1.67
Covalent Bond – share electrons – electronegativity <1.67
Metallic Bond – free moving electrons in “cloud”
Network Bond – extended covalent bonds
Created by C. Ippolito
Dec 2006
Ionic Bonds
• electrons transferred from one element to another
to complete their valence shells
– Cation – positive ion loses electron – metal
– Anion – negative ion gains electron – nonmetal
• Stable Octet
– atoms gain stability by completing their valence shell
– this is done when shell is filled with eight electrons
• Ionic Compound (salt)
– formed from electrovalent attraction of cation for anion
Created by C. Ippolito
Dec 2006
Lewis Dot Diagrams
• used to represent valence shells of atoms
– kernel – nucleus and all inner energy levels
• represented by the element’s symbol
– valence electrons
• represented by dots surrounding the symbol
• determined by the Group or Family in periodic table
Created by C. Ippolito
Dec 2006
Dot Diagrams of Atoms
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14
• Group 18
Created by C. Ippolito
Dec 2006
Dot Diagrams of Ions
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14 – no ion
• Group 18 – no ion
Created by C. Ippolito
Dec 2006
Covalent Bond
• atoms share electrons to complete valence shell
– molecular substance – atoms held together by covalent bonds
• Nonpolar Covalent Bond
– electrons are shared equally – electronegativity <1.3
• Polar Covalent Bond
– electrons are shared unequally
– electronegativity 1.3<<1.67
• Dipole
– molecule has a slightly positive side (δ+)
– molecule has a slightly negative side (δ-)
Created by C. Ippolito
Dec 2006
Nonpolar Covalent Bond
Representations
• Molecular Formula
• Dot Diagram
• Structural Formula
Created by C. Ippolito
Dec 2006
Multiple Covalent Bonds
• Single Bond
– 1 electron pair shared
• Double Bond
– 2 electron pairs shared
• Triple Bond
– 3 electron pairs shared
Created by C. Ippolito
Dec 2006
Hybridization
• rearrangement of electrons within the
valence orbitals during chemical reactions
– sp hybridization in carbon atom
• 1s22s22p2 configuration is changed in bonding
• one 2s electron is “elevated” to “equalize” all 2
orbitals
– 1s22spx1spy1spz1
Created by C. Ippolito
Dec 2006
Resonance
• explains structures that experimentally do
not conform to dot diagrams
– electrons are seen to move from one bond to
another bond and back again
– they “resonate”
Created by C. Ippolito
Dec 2006
VSEPR Modeling
• Valence Shell Electron Pair Repulsion
– used to explain shapes of molecules
– bonded atom’s electron clouds balance forces of
repulsion and attraction
– this “spaces” them apart as far as they possible
can be from each other
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Tetrahedral Shape
– bond angle 109.47o
– CH4
• Trigonal Pyramidal Shape
– bond angle 107o
– NH3
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Trigonal Planar Shape
– bond angle 120o
– SO3
• Bent Shape
– bond angle 105o
– H2O
• Linear Shape
– bond angle 180o
Created by C. Ippolito
Dec 2006
Hydrogen Bonding
• special attraction between dipoles and compounds
with hydrogen
– hydrogen atom with (δ+) slight positive charge forms
weak bond with highly electronegative atoms in other
molecules that have (δ-) slight negative charge
• special properties of water
– ice less dense than water
– high heat of vaporization (cooling property)
• holds DNA molecule halves together allowing replication
Created by C. Ippolito
Dec 2006
Metallic Bond
• metal atoms in solid and liquid state
– “positive ions” in a “sea” of free flowing
electrons
Created by C. Ippolito
Dec 2006
Network Solids
• covalent crystals
– atoms continuously bonded in a definite pattern
– “one giant” molecule
• very hard
• very high melting points
• poor conductors
Created by C. Ippolito
Dec 2006
Ionic Crystals
• ions packed in a regular pattern
– each anion is surrounded by cations
– each cation surrounded by anions
• high melting point
• nonconductive as solid
• conductive as liquid or dissolved
– because “lattice” structure is broken
Created by C. Ippolito
Dec 2006
Slide 14
Chemical Bonding
Objectives:
1.
describe the nature of a chemical bond and its relationship to
valence electrons
2.
compare ionic and covalent bonding
3.
use Lewis Dot Diagrams to represent ionic and covalent compounds
4.
describe the relationship between molecular polarity and bond
polarity
5.
explain the nature and effects of metallic bonding, hydrogen
bonding, and van der Waals forces
6.
compare the structure and properties of polar and nonpolar
molecules
7.
compare the four classes of solids: ionic, molecular, metallic, and
network
Created by C. Ippolito
Dec 2006
Chemical Bonding
• Chemical Bond
– force of attraction that holds atoms together to form
compounds
• Types of Bonds
–
–
–
–
Ionic Bond – transfer electrons – electronegativity >1.67
Covalent Bond – share electrons – electronegativity <1.67
Metallic Bond – free moving electrons in “cloud”
Network Bond – extended covalent bonds
Created by C. Ippolito
Dec 2006
Ionic Bonds
• electrons transferred from one element to another
to complete their valence shells
– Cation – positive ion loses electron – metal
– Anion – negative ion gains electron – nonmetal
• Stable Octet
– atoms gain stability by completing their valence shell
– this is done when shell is filled with eight electrons
• Ionic Compound (salt)
– formed from electrovalent attraction of cation for anion
Created by C. Ippolito
Dec 2006
Lewis Dot Diagrams
• used to represent valence shells of atoms
– kernel – nucleus and all inner energy levels
• represented by the element’s symbol
– valence electrons
• represented by dots surrounding the symbol
• determined by the Group or Family in periodic table
Created by C. Ippolito
Dec 2006
Dot Diagrams of Atoms
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14
• Group 18
Created by C. Ippolito
Dec 2006
Dot Diagrams of Ions
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14 – no ion
• Group 18 – no ion
Created by C. Ippolito
Dec 2006
Covalent Bond
• atoms share electrons to complete valence shell
– molecular substance – atoms held together by covalent bonds
• Nonpolar Covalent Bond
– electrons are shared equally – electronegativity <1.3
• Polar Covalent Bond
– electrons are shared unequally
– electronegativity 1.3<<1.67
• Dipole
– molecule has a slightly positive side (δ+)
– molecule has a slightly negative side (δ-)
Created by C. Ippolito
Dec 2006
Nonpolar Covalent Bond
Representations
• Molecular Formula
• Dot Diagram
• Structural Formula
Created by C. Ippolito
Dec 2006
Multiple Covalent Bonds
• Single Bond
– 1 electron pair shared
• Double Bond
– 2 electron pairs shared
• Triple Bond
– 3 electron pairs shared
Created by C. Ippolito
Dec 2006
Hybridization
• rearrangement of electrons within the
valence orbitals during chemical reactions
– sp hybridization in carbon atom
• 1s22s22p2 configuration is changed in bonding
• one 2s electron is “elevated” to “equalize” all 2
orbitals
– 1s22spx1spy1spz1
Created by C. Ippolito
Dec 2006
Resonance
• explains structures that experimentally do
not conform to dot diagrams
– electrons are seen to move from one bond to
another bond and back again
– they “resonate”
Created by C. Ippolito
Dec 2006
VSEPR Modeling
• Valence Shell Electron Pair Repulsion
– used to explain shapes of molecules
– bonded atom’s electron clouds balance forces of
repulsion and attraction
– this “spaces” them apart as far as they possible
can be from each other
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Tetrahedral Shape
– bond angle 109.47o
– CH4
• Trigonal Pyramidal Shape
– bond angle 107o
– NH3
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Trigonal Planar Shape
– bond angle 120o
– SO3
• Bent Shape
– bond angle 105o
– H2O
• Linear Shape
– bond angle 180o
Created by C. Ippolito
Dec 2006
Hydrogen Bonding
• special attraction between dipoles and compounds
with hydrogen
– hydrogen atom with (δ+) slight positive charge forms
weak bond with highly electronegative atoms in other
molecules that have (δ-) slight negative charge
• special properties of water
– ice less dense than water
– high heat of vaporization (cooling property)
• holds DNA molecule halves together allowing replication
Created by C. Ippolito
Dec 2006
Metallic Bond
• metal atoms in solid and liquid state
– “positive ions” in a “sea” of free flowing
electrons
Created by C. Ippolito
Dec 2006
Network Solids
• covalent crystals
– atoms continuously bonded in a definite pattern
– “one giant” molecule
• very hard
• very high melting points
• poor conductors
Created by C. Ippolito
Dec 2006
Ionic Crystals
• ions packed in a regular pattern
– each anion is surrounded by cations
– each cation surrounded by anions
• high melting point
• nonconductive as solid
• conductive as liquid or dissolved
– because “lattice” structure is broken
Created by C. Ippolito
Dec 2006
Slide 15
Chemical Bonding
Objectives:
1.
describe the nature of a chemical bond and its relationship to
valence electrons
2.
compare ionic and covalent bonding
3.
use Lewis Dot Diagrams to represent ionic and covalent compounds
4.
describe the relationship between molecular polarity and bond
polarity
5.
explain the nature and effects of metallic bonding, hydrogen
bonding, and van der Waals forces
6.
compare the structure and properties of polar and nonpolar
molecules
7.
compare the four classes of solids: ionic, molecular, metallic, and
network
Created by C. Ippolito
Dec 2006
Chemical Bonding
• Chemical Bond
– force of attraction that holds atoms together to form
compounds
• Types of Bonds
–
–
–
–
Ionic Bond – transfer electrons – electronegativity >1.67
Covalent Bond – share electrons – electronegativity <1.67
Metallic Bond – free moving electrons in “cloud”
Network Bond – extended covalent bonds
Created by C. Ippolito
Dec 2006
Ionic Bonds
• electrons transferred from one element to another
to complete their valence shells
– Cation – positive ion loses electron – metal
– Anion – negative ion gains electron – nonmetal
• Stable Octet
– atoms gain stability by completing their valence shell
– this is done when shell is filled with eight electrons
• Ionic Compound (salt)
– formed from electrovalent attraction of cation for anion
Created by C. Ippolito
Dec 2006
Lewis Dot Diagrams
• used to represent valence shells of atoms
– kernel – nucleus and all inner energy levels
• represented by the element’s symbol
– valence electrons
• represented by dots surrounding the symbol
• determined by the Group or Family in periodic table
Created by C. Ippolito
Dec 2006
Dot Diagrams of Atoms
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14
• Group 18
Created by C. Ippolito
Dec 2006
Dot Diagrams of Ions
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14 – no ion
• Group 18 – no ion
Created by C. Ippolito
Dec 2006
Covalent Bond
• atoms share electrons to complete valence shell
– molecular substance – atoms held together by covalent bonds
• Nonpolar Covalent Bond
– electrons are shared equally – electronegativity <1.3
• Polar Covalent Bond
– electrons are shared unequally
– electronegativity 1.3<<1.67
• Dipole
– molecule has a slightly positive side (δ+)
– molecule has a slightly negative side (δ-)
Created by C. Ippolito
Dec 2006
Nonpolar Covalent Bond
Representations
• Molecular Formula
• Dot Diagram
• Structural Formula
Created by C. Ippolito
Dec 2006
Multiple Covalent Bonds
• Single Bond
– 1 electron pair shared
• Double Bond
– 2 electron pairs shared
• Triple Bond
– 3 electron pairs shared
Created by C. Ippolito
Dec 2006
Hybridization
• rearrangement of electrons within the
valence orbitals during chemical reactions
– sp hybridization in carbon atom
• 1s22s22p2 configuration is changed in bonding
• one 2s electron is “elevated” to “equalize” all 2
orbitals
– 1s22spx1spy1spz1
Created by C. Ippolito
Dec 2006
Resonance
• explains structures that experimentally do
not conform to dot diagrams
– electrons are seen to move from one bond to
another bond and back again
– they “resonate”
Created by C. Ippolito
Dec 2006
VSEPR Modeling
• Valence Shell Electron Pair Repulsion
– used to explain shapes of molecules
– bonded atom’s electron clouds balance forces of
repulsion and attraction
– this “spaces” them apart as far as they possible
can be from each other
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Tetrahedral Shape
– bond angle 109.47o
– CH4
• Trigonal Pyramidal Shape
– bond angle 107o
– NH3
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Trigonal Planar Shape
– bond angle 120o
– SO3
• Bent Shape
– bond angle 105o
– H2O
• Linear Shape
– bond angle 180o
Created by C. Ippolito
Dec 2006
Hydrogen Bonding
• special attraction between dipoles and compounds
with hydrogen
– hydrogen atom with (δ+) slight positive charge forms
weak bond with highly electronegative atoms in other
molecules that have (δ-) slight negative charge
• special properties of water
– ice less dense than water
– high heat of vaporization (cooling property)
• holds DNA molecule halves together allowing replication
Created by C. Ippolito
Dec 2006
Metallic Bond
• metal atoms in solid and liquid state
– “positive ions” in a “sea” of free flowing
electrons
Created by C. Ippolito
Dec 2006
Network Solids
• covalent crystals
– atoms continuously bonded in a definite pattern
– “one giant” molecule
• very hard
• very high melting points
• poor conductors
Created by C. Ippolito
Dec 2006
Ionic Crystals
• ions packed in a regular pattern
– each anion is surrounded by cations
– each cation surrounded by anions
• high melting point
• nonconductive as solid
• conductive as liquid or dissolved
– because “lattice” structure is broken
Created by C. Ippolito
Dec 2006
Slide 16
Chemical Bonding
Objectives:
1.
describe the nature of a chemical bond and its relationship to
valence electrons
2.
compare ionic and covalent bonding
3.
use Lewis Dot Diagrams to represent ionic and covalent compounds
4.
describe the relationship between molecular polarity and bond
polarity
5.
explain the nature and effects of metallic bonding, hydrogen
bonding, and van der Waals forces
6.
compare the structure and properties of polar and nonpolar
molecules
7.
compare the four classes of solids: ionic, molecular, metallic, and
network
Created by C. Ippolito
Dec 2006
Chemical Bonding
• Chemical Bond
– force of attraction that holds atoms together to form
compounds
• Types of Bonds
–
–
–
–
Ionic Bond – transfer electrons – electronegativity >1.67
Covalent Bond – share electrons – electronegativity <1.67
Metallic Bond – free moving electrons in “cloud”
Network Bond – extended covalent bonds
Created by C. Ippolito
Dec 2006
Ionic Bonds
• electrons transferred from one element to another
to complete their valence shells
– Cation – positive ion loses electron – metal
– Anion – negative ion gains electron – nonmetal
• Stable Octet
– atoms gain stability by completing their valence shell
– this is done when shell is filled with eight electrons
• Ionic Compound (salt)
– formed from electrovalent attraction of cation for anion
Created by C. Ippolito
Dec 2006
Lewis Dot Diagrams
• used to represent valence shells of atoms
– kernel – nucleus and all inner energy levels
• represented by the element’s symbol
– valence electrons
• represented by dots surrounding the symbol
• determined by the Group or Family in periodic table
Created by C. Ippolito
Dec 2006
Dot Diagrams of Atoms
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14
• Group 18
Created by C. Ippolito
Dec 2006
Dot Diagrams of Ions
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14 – no ion
• Group 18 – no ion
Created by C. Ippolito
Dec 2006
Covalent Bond
• atoms share electrons to complete valence shell
– molecular substance – atoms held together by covalent bonds
• Nonpolar Covalent Bond
– electrons are shared equally – electronegativity <1.3
• Polar Covalent Bond
– electrons are shared unequally
– electronegativity 1.3<<1.67
• Dipole
– molecule has a slightly positive side (δ+)
– molecule has a slightly negative side (δ-)
Created by C. Ippolito
Dec 2006
Nonpolar Covalent Bond
Representations
• Molecular Formula
• Dot Diagram
• Structural Formula
Created by C. Ippolito
Dec 2006
Multiple Covalent Bonds
• Single Bond
– 1 electron pair shared
• Double Bond
– 2 electron pairs shared
• Triple Bond
– 3 electron pairs shared
Created by C. Ippolito
Dec 2006
Hybridization
• rearrangement of electrons within the
valence orbitals during chemical reactions
– sp hybridization in carbon atom
• 1s22s22p2 configuration is changed in bonding
• one 2s electron is “elevated” to “equalize” all 2
orbitals
– 1s22spx1spy1spz1
Created by C. Ippolito
Dec 2006
Resonance
• explains structures that experimentally do
not conform to dot diagrams
– electrons are seen to move from one bond to
another bond and back again
– they “resonate”
Created by C. Ippolito
Dec 2006
VSEPR Modeling
• Valence Shell Electron Pair Repulsion
– used to explain shapes of molecules
– bonded atom’s electron clouds balance forces of
repulsion and attraction
– this “spaces” them apart as far as they possible
can be from each other
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Tetrahedral Shape
– bond angle 109.47o
– CH4
• Trigonal Pyramidal Shape
– bond angle 107o
– NH3
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Trigonal Planar Shape
– bond angle 120o
– SO3
• Bent Shape
– bond angle 105o
– H2O
• Linear Shape
– bond angle 180o
Created by C. Ippolito
Dec 2006
Hydrogen Bonding
• special attraction between dipoles and compounds
with hydrogen
– hydrogen atom with (δ+) slight positive charge forms
weak bond with highly electronegative atoms in other
molecules that have (δ-) slight negative charge
• special properties of water
– ice less dense than water
– high heat of vaporization (cooling property)
• holds DNA molecule halves together allowing replication
Created by C. Ippolito
Dec 2006
Metallic Bond
• metal atoms in solid and liquid state
– “positive ions” in a “sea” of free flowing
electrons
Created by C. Ippolito
Dec 2006
Network Solids
• covalent crystals
– atoms continuously bonded in a definite pattern
– “one giant” molecule
• very hard
• very high melting points
• poor conductors
Created by C. Ippolito
Dec 2006
Ionic Crystals
• ions packed in a regular pattern
– each anion is surrounded by cations
– each cation surrounded by anions
• high melting point
• nonconductive as solid
• conductive as liquid or dissolved
– because “lattice” structure is broken
Created by C. Ippolito
Dec 2006
Slide 17
Chemical Bonding
Objectives:
1.
describe the nature of a chemical bond and its relationship to
valence electrons
2.
compare ionic and covalent bonding
3.
use Lewis Dot Diagrams to represent ionic and covalent compounds
4.
describe the relationship between molecular polarity and bond
polarity
5.
explain the nature and effects of metallic bonding, hydrogen
bonding, and van der Waals forces
6.
compare the structure and properties of polar and nonpolar
molecules
7.
compare the four classes of solids: ionic, molecular, metallic, and
network
Created by C. Ippolito
Dec 2006
Chemical Bonding
• Chemical Bond
– force of attraction that holds atoms together to form
compounds
• Types of Bonds
–
–
–
–
Ionic Bond – transfer electrons – electronegativity >1.67
Covalent Bond – share electrons – electronegativity <1.67
Metallic Bond – free moving electrons in “cloud”
Network Bond – extended covalent bonds
Created by C. Ippolito
Dec 2006
Ionic Bonds
• electrons transferred from one element to another
to complete their valence shells
– Cation – positive ion loses electron – metal
– Anion – negative ion gains electron – nonmetal
• Stable Octet
– atoms gain stability by completing their valence shell
– this is done when shell is filled with eight electrons
• Ionic Compound (salt)
– formed from electrovalent attraction of cation for anion
Created by C. Ippolito
Dec 2006
Lewis Dot Diagrams
• used to represent valence shells of atoms
– kernel – nucleus and all inner energy levels
• represented by the element’s symbol
– valence electrons
• represented by dots surrounding the symbol
• determined by the Group or Family in periodic table
Created by C. Ippolito
Dec 2006
Dot Diagrams of Atoms
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14
• Group 18
Created by C. Ippolito
Dec 2006
Dot Diagrams of Ions
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14 – no ion
• Group 18 – no ion
Created by C. Ippolito
Dec 2006
Covalent Bond
• atoms share electrons to complete valence shell
– molecular substance – atoms held together by covalent bonds
• Nonpolar Covalent Bond
– electrons are shared equally – electronegativity <1.3
• Polar Covalent Bond
– electrons are shared unequally
– electronegativity 1.3<<1.67
• Dipole
– molecule has a slightly positive side (δ+)
– molecule has a slightly negative side (δ-)
Created by C. Ippolito
Dec 2006
Nonpolar Covalent Bond
Representations
• Molecular Formula
• Dot Diagram
• Structural Formula
Created by C. Ippolito
Dec 2006
Multiple Covalent Bonds
• Single Bond
– 1 electron pair shared
• Double Bond
– 2 electron pairs shared
• Triple Bond
– 3 electron pairs shared
Created by C. Ippolito
Dec 2006
Hybridization
• rearrangement of electrons within the
valence orbitals during chemical reactions
– sp hybridization in carbon atom
• 1s22s22p2 configuration is changed in bonding
• one 2s electron is “elevated” to “equalize” all 2
orbitals
– 1s22spx1spy1spz1
Created by C. Ippolito
Dec 2006
Resonance
• explains structures that experimentally do
not conform to dot diagrams
– electrons are seen to move from one bond to
another bond and back again
– they “resonate”
Created by C. Ippolito
Dec 2006
VSEPR Modeling
• Valence Shell Electron Pair Repulsion
– used to explain shapes of molecules
– bonded atom’s electron clouds balance forces of
repulsion and attraction
– this “spaces” them apart as far as they possible
can be from each other
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Tetrahedral Shape
– bond angle 109.47o
– CH4
• Trigonal Pyramidal Shape
– bond angle 107o
– NH3
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Trigonal Planar Shape
– bond angle 120o
– SO3
• Bent Shape
– bond angle 105o
– H2O
• Linear Shape
– bond angle 180o
Created by C. Ippolito
Dec 2006
Hydrogen Bonding
• special attraction between dipoles and compounds
with hydrogen
– hydrogen atom with (δ+) slight positive charge forms
weak bond with highly electronegative atoms in other
molecules that have (δ-) slight negative charge
• special properties of water
– ice less dense than water
– high heat of vaporization (cooling property)
• holds DNA molecule halves together allowing replication
Created by C. Ippolito
Dec 2006
Metallic Bond
• metal atoms in solid and liquid state
– “positive ions” in a “sea” of free flowing
electrons
Created by C. Ippolito
Dec 2006
Network Solids
• covalent crystals
– atoms continuously bonded in a definite pattern
– “one giant” molecule
• very hard
• very high melting points
• poor conductors
Created by C. Ippolito
Dec 2006
Ionic Crystals
• ions packed in a regular pattern
– each anion is surrounded by cations
– each cation surrounded by anions
• high melting point
• nonconductive as solid
• conductive as liquid or dissolved
– because “lattice” structure is broken
Created by C. Ippolito
Dec 2006
Slide 18
Chemical Bonding
Objectives:
1.
describe the nature of a chemical bond and its relationship to
valence electrons
2.
compare ionic and covalent bonding
3.
use Lewis Dot Diagrams to represent ionic and covalent compounds
4.
describe the relationship between molecular polarity and bond
polarity
5.
explain the nature and effects of metallic bonding, hydrogen
bonding, and van der Waals forces
6.
compare the structure and properties of polar and nonpolar
molecules
7.
compare the four classes of solids: ionic, molecular, metallic, and
network
Created by C. Ippolito
Dec 2006
Chemical Bonding
• Chemical Bond
– force of attraction that holds atoms together to form
compounds
• Types of Bonds
–
–
–
–
Ionic Bond – transfer electrons – electronegativity >1.67
Covalent Bond – share electrons – electronegativity <1.67
Metallic Bond – free moving electrons in “cloud”
Network Bond – extended covalent bonds
Created by C. Ippolito
Dec 2006
Ionic Bonds
• electrons transferred from one element to another
to complete their valence shells
– Cation – positive ion loses electron – metal
– Anion – negative ion gains electron – nonmetal
• Stable Octet
– atoms gain stability by completing their valence shell
– this is done when shell is filled with eight electrons
• Ionic Compound (salt)
– formed from electrovalent attraction of cation for anion
Created by C. Ippolito
Dec 2006
Lewis Dot Diagrams
• used to represent valence shells of atoms
– kernel – nucleus and all inner energy levels
• represented by the element’s symbol
– valence electrons
• represented by dots surrounding the symbol
• determined by the Group or Family in periodic table
Created by C. Ippolito
Dec 2006
Dot Diagrams of Atoms
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14
• Group 18
Created by C. Ippolito
Dec 2006
Dot Diagrams of Ions
• Group 1
• Group 15
• Group 2
• Group 16
• Group 13
• Group 17
• Group 14 – no ion
• Group 18 – no ion
Created by C. Ippolito
Dec 2006
Covalent Bond
• atoms share electrons to complete valence shell
– molecular substance – atoms held together by covalent bonds
• Nonpolar Covalent Bond
– electrons are shared equally – electronegativity <1.3
• Polar Covalent Bond
– electrons are shared unequally
– electronegativity 1.3<<1.67
• Dipole
– molecule has a slightly positive side (δ+)
– molecule has a slightly negative side (δ-)
Created by C. Ippolito
Dec 2006
Nonpolar Covalent Bond
Representations
• Molecular Formula
• Dot Diagram
• Structural Formula
Created by C. Ippolito
Dec 2006
Multiple Covalent Bonds
• Single Bond
– 1 electron pair shared
• Double Bond
– 2 electron pairs shared
• Triple Bond
– 3 electron pairs shared
Created by C. Ippolito
Dec 2006
Hybridization
• rearrangement of electrons within the
valence orbitals during chemical reactions
– sp hybridization in carbon atom
• 1s22s22p2 configuration is changed in bonding
• one 2s electron is “elevated” to “equalize” all 2
orbitals
– 1s22spx1spy1spz1
Created by C. Ippolito
Dec 2006
Resonance
• explains structures that experimentally do
not conform to dot diagrams
– electrons are seen to move from one bond to
another bond and back again
– they “resonate”
Created by C. Ippolito
Dec 2006
VSEPR Modeling
• Valence Shell Electron Pair Repulsion
– used to explain shapes of molecules
– bonded atom’s electron clouds balance forces of
repulsion and attraction
– this “spaces” them apart as far as they possible
can be from each other
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Tetrahedral Shape
– bond angle 109.47o
– CH4
• Trigonal Pyramidal Shape
– bond angle 107o
– NH3
Created by C. Ippolito
Dec 2006
Molecular Shapes
• Trigonal Planar Shape
– bond angle 120o
– SO3
• Bent Shape
– bond angle 105o
– H2O
• Linear Shape
– bond angle 180o
Created by C. Ippolito
Dec 2006
Hydrogen Bonding
• special attraction between dipoles and compounds
with hydrogen
– hydrogen atom with (δ+) slight positive charge forms
weak bond with highly electronegative atoms in other
molecules that have (δ-) slight negative charge
• special properties of water
– ice less dense than water
– high heat of vaporization (cooling property)
• holds DNA molecule halves together allowing replication
Created by C. Ippolito
Dec 2006
Metallic Bond
• metal atoms in solid and liquid state
– “positive ions” in a “sea” of free flowing
electrons
Created by C. Ippolito
Dec 2006
Network Solids
• covalent crystals
– atoms continuously bonded in a definite pattern
– “one giant” molecule
• very hard
• very high melting points
• poor conductors
Created by C. Ippolito
Dec 2006
Ionic Crystals
• ions packed in a regular pattern
– each anion is surrounded by cations
– each cation surrounded by anions
• high melting point
• nonconductive as solid
• conductive as liquid or dissolved
– because “lattice” structure is broken
Created by C. Ippolito
Dec 2006