1. Ch. 6 – Molecular Structure
II. Molecular Geometry

2. A. VSEPR Theory Valence Shell Electron Pair Repulsion Theory
Electron pairs orient themselves so that valence electrons are as far apart as possible

3. Lone pairs repel more strongly than bonding pairs!!!
A. VSEPR Theory
Types of e- Pairs
Bonding pairs - form bonds
Lone pairs - nonbonding e-
Lone pairs repel more strongly than bonding pairs!!!

4. A. VSEPR Theory Lone pairs reduce the bond angle between atoms.

5. B. Determining Molecular Shape
Draw the Lewis Diagram.
Count up e- pairs on central atom.
double/triple bonds = ONE pair
Shape is determined by the # of bonding pairs and lone pairs.
Know the 8 common shapes
& their bond angles!

6. C. Common Molecular Shapes
2 total electron pairs
*2 bonding pairs
*0 lone pairs
Note: Beryllium does not follow the octet rule. Beryllium is complete with 4 valence electrons
BeH2
LINEAR
180°

7. C. Common Molecular Shapes
3 total electron pairs
*3 bonding pairs
*0 lone pairs
BF3
TRIGONAL PLANAR
120°
Note: Boron is also an exception to the octet rule. Boron is complete with 6 valence electrons

8. C. Common Molecular Shapes
3 total pairs
*2 bonding pairs
*1 lone pair
SO2
BENT
<120°

9. C. Common Molecular Shapes
4 total pairs
*4 bonding pairs
*0 lone pairs
CH4
TETRAHEDRAL
109.5°

10. C. Common Molecular Shapes
4 total pairs
*3 bonding pairs
*1 lone pair
NH3
TRIGONAL PYRAMIDAL
107°

11. C. Common Molecular Shapes
4 total pairs
*2 bonding pairs
*2 lone pairs
H2O
BENT
104.5°

12. C. Common Molecular Shapes
5 total pairs
*5 bonding pairs
*0 lone
PCl5
TRIGONAL BIPYRAMIDAL
120°/90°

13. C. Common Molecular Shapes
6 total pairs
*6 bonding pairs
*0 lone pairs
SF6
OCTAHEDRAL
90°

14. D. Examples
F P F F
PF3
4 total
3 bond
1 lone
TRIGONAL PYRAMIDAL
107°

15. D. Examples
O C O
CO2
2 total
2 bonding pairs
0 lone
LINEAR
180°

16. III. Molecular Polarity
Molecular Structure
III. Molecular Polarity

17. + - A. Dipole Moment H Cl Direction of the polar bond in a molecule.
Arrow points toward the more electronegative atom.
H Cl + -

18. B. Determining Molecular Polarity
Depends on:
dipole moments
molecular shape

19. B. Determining Molecular Polarity
Nonpolar Molecules
Dipole moments are symmetrical and cancel out.
BF3 F B

20. B. Determining Molecular Polarity
Polar Molecules
Dipole moments are asymmetrical and don’t cancel .
H2O H O
net
dipole
moment

21. B. Determining Molecular Polarity
Therefore, polar molecules have...
asymmetrical shape (lone pairs) or
asymmetrical atoms
CHCl3 H Cl
net
dipole
moment