1. VSEPR and CARBON CHEMISTRY
Unit 3

2. VSEPR (Valence Shell Electron Pair Repulsion
2 Rules Govern VSEPR:
Regions of high electron concentration repel one another. to minimize these repulsions these regions move as far away from each other as possible.
We do not distinguish between single and multiple bonds.
**Remember VSEPR simply extends Lewis’s theory of bonding to account for molecular shapes by adding rules that account for bond angles.
***When naming a shape we only consider the position of atoms not lone pairs.

3. Linear Geometry. Simple arragnement Notice the bond angle is 180°
AX CO2
AX H2
AXE CN-
Notice the bond angle is 180°

4. Angular/ Bent Geometry
Simple Arrangement
AX2E H2O
AX2E SeBr2
AXE Cl2
Notice the bond
angle is 104°

5. Trigonal Planar Geometry
Simple arrangement:
AX AlBr3 BF3 COCl2
The bond angles
will be 120°

6. Trigonal Pyrimidal Geometry
Simple arrangement:
AX3E NH3
Bond angles are 109.5°

7. Tetrahedral Geometry Simple arrangement: The bond angles are 109.5°
AX CH CH3Cl
The bond angles
are 109.5°

8. Trigonal Bipyramidal Simple Arrangement Bond angles are 90° and 120°
AX5 PCl5
Bond angles are 90°
and 120°

9. Octahedral Geometry Simple Arrangement: Bond anlges are all 90°
AX6 SF6
Bond anlges are all 90°

10. Sigma and Pi Bonds A single bond has a a σ-bond.
A σ-bond is the merging of two atomic
orbitals by overlap.

11. Sigma and Pi Bonds A double bond is a σ-bond plus one π-bond.
A π-bond is formed when electron is p-orbitals
overlap to share electrons.

12. Sigma and Pi bonds
A triple bond consists of a σ-bond plus two π-bonds.

13. Carbon Chemistry single bonds between carbons end in -ane. (Alkanes)
Double bonds between carbons
end in -ene. (Alkenes)
Triple Bonds between carbons
end in -yne. (Alkynes)

14. Arenes (Aromatic Carbon Compounds “Rings”)
Aromatic Benzene