1. Molecular Shape Section 9.4
Chemistry

2. Objectives Discuss the VSEPR bonding theory
Predict the shape of and the bond angles in a molecule
Define hybridization

3. The Shape of Molecules
The shape of molecules determines reaction ability
The model we use is the VSEPR model
Valence Shell Electron Pair Repulsion

4. VSEPR Model
Minimizes the repulsion of shared and unshared pairs of electrons around the central atom
7 key shapes you will need to be able to draw and identify

5. Linear Molecular Shape
Example: BeCl2
Total Pairs of Electrons: 2
Shared Pairs of Electrons: 2
Lone Pairs: 0
Bond Angle: 180°
Hybrid Orbitals: sp

6. Trigonal Planar Example: AlCl3 Total Pairs of Electrons: 3
Shared Pairs of Electrons: 3
Lone Pairs of Electrons: 0
Bond Angle: 120°
Hybrid Orbitals: sp²

7. Tetrahedral Example: CH4 Total Pairs of Electrons: 4
Shared Pairs of Electrons: 4
Lone Pairs of Electrons: 0
Bond Angle: °
Hybrid Orbitals: sp³

8. Trigonal Pyramidal Example: PH3 Total Pairs of Electrons: 4
Shared Pairs of Electrons: 3
Lone Pairs of Electrons: 1
Bond Angle: °
Hybrid Orbitals: sp³

9. Bent Example: H2O Total Pairs of Electrons: 4
Shared Pairs of Electrons: 2
Lone Pairs of Electrons: 2
Bond Angle: °
Hybrid Orbitals: sp³

10. Trigonal Bipyramidal Example: NbBr5 Total Pairs of Electrons: 5
Shared Pairs of Electrons: 5
Lone Pairs of Electrons:0
Bond Angle: 90°, 120°
Hybrid Orbitals: sp³d

11. Octahedral Example: SF6 Total Pairs of Electrons: 6
Shared Pairs of Electrons: 6
Lone Pairs of Electrons: 0
Bond Angle: 90°
Hybrid Orbitals: sp³d²

12. Hybridization
Hybridization: A process in which atomic orbitals are mixed to form new, identical hybrid orbitals
Carbon is the most common
The number of hybrid orbitals = the number of total pairs of electrons

13. Homework
54-59 on page 262