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, H
2
O, CH
4
?
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 C
3
H
6
.

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 SO
2
. 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 intramolecular 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
H
2
O
2
Cl
2
Br
2
CH
4
CCl
4
C
6
H
6
PH
3
NH
3
H
2
S
H
2
O
HF
HCl
ICl
B.P. (1 atm) in o C
-253
-183
-34
59
-164
77
80
-88
-33
-61
100
20
-85
97

Boiling Points and Bonding Types
Bonding Type
Ionic
Metallic
Substance
NaCl
MgF
2
Cu
Fe
W
B.P. (1 atm) in o C
1413
2239
2567
2750
5660

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