Valence Bond Theory and Hybridization

σ bond

σ bond

cylindrically symmetric about the bond axis; no nodal plane along the bond axis

𝜋 bond

electron density in 2 lobes with a single nodal plane along the bond axis

Single bond

𝜋 bond

Double bond

σ bond + 𝜋 bond

Triple bond

σ bond + 𝜋 bond + 𝜋 bond

Exception

single-bonded terminal atoms

Electron promotion serves to

increase the number of unpaired electrons; if you have an empty orbital you can promote one of your electrons to that orbital

The hybrid orbitals only differ in

their orientation in space

2 hybrid orbitals =

sp

3 hybrid orbitals =

sp²

4 hybrid orbitals =

sp³

In valence bond theory, bonds result from

the pairing of unpaired electrons from the valence shell atomic orbitals

Energy for the initial electron promotion comes from

bonding

Molecules can't rotate around a

double bond