Transcript Chapter 11
Chapter 6 Chemical Bonds
Compounds H O
+
H
H
2
O -
Compounds H
HCl
Cl
Outer Energy Level Atom is stable: outer energy level is filled.
Eight(8) electrons. (2 e- for first level.) The outer energy level is called the valence shell.
Electrons in the outer shell are called Valence Electrons .
Electron Dot Diagram Represent Valence Electrons N Group 15 – 5A 5 Valence e -
He Ar
Stable Atoms
Ne Xe Kr Rn
Valence Electrons 1 valence e -
Cs
Valence Electrons 2 valence e -
Ca
Valence Electrons Transition Elements For This Class
Valence Electrons 3 valence e -
Ga
Valence Electrons 4 valence e -
Sn
Valence Electrons 5 valence e -
P
Valence Electrons 6 valence e -
S
Valence Electrons 7 valence e -
I
Valence Electrons 8valence e -
Ne
Making Atoms Stable Transferred!
Na Cl
+
Na Cl
-
Making Atoms Stable
Cl
Shared
Cl Cl Cl
Kinds of Chemical Bonds
Electron Loss, Gain or Share
Ionic Bonds
Ion
The charged particle that results when an atom
gains
or
loses
one or more electrons.
Anion Anions are the result of atoms gaining electrons.
Anions have a negative charge.
Br
-
35p + 35e -
Anion Atoms change their name on becoming an anion.
“ide” is added to their name.
o ide
9p + 9e Gain e -
F Fluorine
Ion 9p + 10e -
F
-
Fluoride
Cation Cations are the result of atoms losing electrons.
Cations have a positive charge.
2 +
20p +
Ca
20e -
3p + 3e Ion 3p + 2e -
Li
Lose e -
Li
+ Lithium
Ionic Bonding
Bonding that occurs between ions or the
losing
or
gaining
electrons.
Ionic Bond
Na Na Cl Cl
NaCl
Sodium Na loses one electron becomes Na +1 Chlorine Cl gains one electron becomes Cl -1 Result Sodium Chloride - Na Cl
Cl
Ionic Bonding
Cl Ca Ca Cl Cl
CaCl 2
Calcium Ca loses two electrons becomes Ca 2+ Chlorine Cl gains one electron becomes Cl Result Calcium Chloride – CaCl 2
Ionic Bond Metals tend to lose electron.
Non-metal tend to gain electrons.
Metals combine with Non-metals
Ionization Energy The amount of energy needed to remove an electron from an atom.
Crystal Lattices Solids whose particles arrange in a lattice structure.
Properties of Ionic Compounds Strong Attraction between Ions.
High Melting Point (Solid) Shatter (Crystal) Melted or Dissolved Good Conductor of Electricity
Homework 6-1
Section 6-1: Worksheet Electron Dot Worksheet Due 12/9/08
Covalent Bond
Atoms that combine by sharing electrons.
Cl
Electron Sharing
Cl
2
Cl
Making Atoms Stable
Cl
Shared
Cl Cl Cl
Shared
H + O + H H
2
O
H Shared
O
H
Multiple Covalent Bonds Atoms that share more than one pair of electrons.
O + O O
2
O
Shared O
O O Double Bond
N + N N
2
Shared
N N N N Triple Bond
Molecule
A neutral particle that is formed when atoms bond covalently .
Unequal Sharing of Electrons Different elements do not share electrons evenly.
As you go left to right in the periodic table, elements have a greater attraction to electrons.
N C
Unequal Sharing of Electrons Molecule that are formed have polarity. The molecule formed will have a positive side and a negative side.
delta δ Polar Molecules
+
H Cl δ
-
Chlorine attracts e- more!!
Polarity ???
Type of Atoms Shape of Molecule
δ +
C
Polar δ δ +
O
H
δ + Polar
O
δ -
H
δ +
O
2 Non-Polar
O
δ δ +
C
δ + Non-Polar
O
δ δ +
CH
4 δ + δ + δ δ + δ +
NaCl Not a Molecule
Attraction between Molecule δ + δ + δ -
Attraction between Molecule Non-Polar – weaker attraction •Lower Boiling Point – Gas •Evaporate quickly •Low Surface Tension
Attraction between Molecule Polar – Greater attraction •Higher Boiling Point – Liquid •Evaporate slower •Higher Surface Tension
Homework 6-2
Section 6-2 Worksheet Due 12/10/08
Section 6-3 Naming Compounds and Writing Formulas
Naming Binary Compounds Binary Compounds
Two
Elements
Rules for naming
Binary Compounds.
Begin with the
Cation
(Positive Charge)
The Anion (-) is changed to end in ”ide”.
Binary Compounds
Chlorine and Magnesium Magnesium - 2 + - Cation Chlorine – 1 - Anion
Magnesium Chlor ide
Binary Compounds
Sodium and Sulfur Sodium - 1 + - Cation Sulfur – 2 - Anion
Sodium Sulf ide
Binary Compounds
Lithium and Oxygen Lithium - 1 + - Cation Oxygen – 2 - Anion
Lithium Oxide
Metals with Multiple Ion (Transition Metals)
Cu
+
Copper(I) Cu
2+
Copper(II)
Copper and Oxygen
Cu
+
O
2-
Cu
2
O
Copper(I) Oxide
Copper and Oxygen
Cu
2+
O
2-
Cu O
Copper(II) Oxide
Polyatomic Ions
A group of covalently bonded atoms that act as one charged atom. These ions can combine with other elements and ions.
Examples of Polyatomic Ions
Ammonium NH 4 N H (3-) + 4(1+) = 1+ (NH 4 ) +
Examples of Polyatomic Ions
Hydroxide OH O H (2-) + (1+) = 1 (OH) -
Carbonate CO 3 C O (4+) + ((2-) X 3) (4+) + (6-) = 2 (CO 3 ) 2-
Writing formulas for Ionic Compounds
Example #1 Write the chemical formula for the compound of silver and sulfur.
Silver Ag 1+ Sulfur: S 2 ( ?
X 1) + ( ?
X-2) = 0 ( 2 X 1) + ( 1 X-2) = 0 Ag 2 S
Example #2 Write the chemical formula for the compound of aluminum and oxygen.
Aluminum: Al 3+ Oxygen: 0 2 ( ?
X +3) + ( ?
X-2) = 0 ( 2 X +3) + ( 3 X-2) = 0 Al 2 0 3
Crisscross Method Write the chemical formula for the compound of boron and sulfur.
B
3+
S
2-
B
2
S
3
Crisscross Method Write the chemical formula for the compound of sodium and phosphorus.
Na
+
P
3-
Na
3
P
Find the formula for calcium hydroxide.
2+
Ca OH
1-
Ca(OH)
2
Describing Molecular Compounds The name and formula of a molecular compound describe the type and number of atoms in a molecule of a compound.
Naming Molecules In general, the most metallic element appears first. (Left and bottom in Periodic Table) Second element change ending to “-ide” .
Use prefixes to tell how many.
If there is only one of the first element no prefix is used .
Prefixes for Naming Molecules
# Atoms Prefix # Atoms Prefix
4 5 1 2 3 mono di tri tetra penta 6 7 8 9 10 hexa hepta octa nona deca-
CO
Name these molecule Carbon Monoxide
Name these molecule
CO
2 Carbon Dioxide
Name these molecule
N
2
O
4 Dinitrogen Tetraoxide
Name these molecule
P
2
O
5 Diphosphorus Pentaoxide
Writing Molecular Formulas Di phophorus Tetra fluoride P F
4
Homework 6-3
Section 6-3 Worksheet Due 12/16/08
Structures of Metals A
metallic bond
is the attraction between a metal cation and the shared electrons that surround it.
+ + + + + + + + + + + + + + + + + + + +
Sea of Valence Electrons The negatively charged electrons act as a "cement" that hold the positively charged metal ions in their relatively fixed positions.
Metals are good Conductors of Heat and Electricity This is directly due to the mobility of the electrons.
Metal Hardness The "cement" effect of the electrons determines the hardness of the metal.
Metal Luster This is due to the uniform way that the valence electrons of the metal absorb and re-emit light energy.
Metal are Malleable and Ductile The metal cations and electrons can "flow" around each other, without breaking the crystal structure.
Ductile
Alloys An
alloy
is a mixture of two or more elements, at least one of which is a metal.
Scientists can design alloys with specific properties by varying the types and amounts of elements in an alloy.
Copper Alloys
Steel Alloys
Homework 6-4
Finish Packet Due 12/19/08 Test: 12/23/08 Project: 12/22/08
Corrosive “Tear Apart”
Recycle
Homework 3-14
Section 11-3 Wrap-up Page: 313 Worksheet Due 3/6/06
Writing Formulas Oxidation Numbers
The name given to the combining ability of an atom.
Na
Oxidation Numbers
Na
1+ 11p+ 11e 11p+ 10e-
F
Oxidation Numbers
F
1 9p+ 9e 9p+ 10e-
N
Oxidation Numbers
N
3 7p+ 7e 7p+ 10e-
N
Oxidation Numbers
N
3 7p+ 7e 7p+ 10e-
Ca Ca
2+ 20p+ 20e 20p+ 18e-
Group
1 2 3-12 Transition Elements 13 14
Metals Oxidation Number
1+ 2+ tend to have more than one 3+ 2+ or 4+
Group Nonmetals Oxidation Number
15 16 17 3 2 1-
Homework 11-4
Practice Problems: 1-2 Page: 316,318 Due 3/15/04
Homework 11-5
Practice Problems: 1-2 Page: 318 Due 3/17/04
Hydrated Crystals Hydrate:
Crystal containing a definite number of water molecules.
H 2 0 H 2 0 H 2 0 CuSO 4 H 2 0 H 2 O CuSO4 5 H 2 O
Anhydrous
A compound with no water.
1 Na Cl Na
1+
Cl
1-
NaCl
2 F Ca Ca
2+
F
1-
CaF
2
F
3 O Al Al O O
3 Al
3+
O
2-
Al
2
O
3
4 H N H
+
N
3-
H
3
N H H
5 K S K
+
S
2-
K
2
S K
6 Ca
2+
NO
3 -
Ca(NO
3
)
2
7 Mg
2+
SO
4 2-
MgSO
4
8 Ga
3+
CO
3 2-
Ga
2
(CO
3
)
3
9 NH
4 +
PO
4 3-
(NH
4
)
3
PO
4
10 Na
+
NO
2 -
NaNO
2