Transcript Molecular Geometry - Madison Public Schools

Chemical Bonding
Molecular Geometry
Ch. 6 Sections 1-4 Review
1. In general, what determines whether atoms will
form chemical bonds?
Atoms will form a chemical bond if their potential
energy is lowered in doing so.
2. Describe the difference between ionic and
covalent bonding.
Ionic bonds form as a result of the transfer of electrons
between two atoms with a large difference in
electronegativity. Covalent bonds form when
electrons are shared between two atoms of similar or
slightly different electronegativity.
Ch. 6 Sections 1-4 Review
3. What types of bonds form between the
following pairs of atoms: Ca-Cl, O-H, O-O?
Ionic, polar covalent, nonpolar covalent
4. What is the meaning of the word polar, as
applied to chemical bonding?
Polar refers to bonds that have an uneven distribution
of charge.
5. What type of bonding exists (ionic or covalent)
in the compounds: NaCl, H2O, CH4?
Ionic, covalent, covalent
Ch. 6 Sections 1-4 Review
6. List 3 properties of ionic compounds.
Hardness, brittleness, electrical conductivity in molten
state, high melting and boiling points.
7. What accounts for the properties of ionic
compounds listed above?
Cations and anions are arranged in a crystal lattice.
8. Draw the Lewis dot diagram for C3H6.
Ch. 6 Sections 1-4 Review
9. How are single, double, and triple covalent
bonds different?
One, two, and three pairs of electrons are shared; bond
energy increases with the number of bonds and
bond length decreases with the number of bonds.
10.Draw the Lewis dot structure for SO2. Show
both resonance structures.
Ch. 6 Sections 1-4 Review
11.What properties of metals contribute to their
tendency to form metallic bonds?
Most metals have unfilled outermost orbitals, low
ionization energies, and low electronegativities.
12.What are some common properties of metals?
Electrical and thermal conductivity, luster, malleability,
ductility, high melting and boiling points
Hybridization
Hybridization – mixing of atomic orbitals of
similar energy to produce new orbitals of equal
energy
Hybridization
Intermolecular Forces
• Covalent, ionic, and metallic bonds can be
considered to be intra-molecular forces
Intermolecular Forces- forces of attraction
between molecules; weaker than covalent,
ionic, and metallic bonds.
Boiling Points and Bonding Types
Bonding Type
Nonpolar covalent
Polar Covalent
Substance
B.P. (1 atm) in oC
H2
-253
O2
-183
Cl2
-34
Br2
59
CH4
-164
CCl4
77
C6H6
80
PH3
-88
NH3
-33
H 2S
-61
H 2O
100
HF
20
HCl
-85
ICl
97
Boiling Points and Bonding Types
Bonding Type
Substance
B.P. (1 atm) in oC
Ionic
NaCl
1413
MgF2
2239
Cu
2567
Fe
2750
W
5660
Metallic
Molecular Polarity
• Molecular polarity depends on the polarity of the
bonds that make up a compound and the molecular
shape.
• A dipole moment results when a polar molecule has a
center for positive charge separate from a center for
negative charge