1. Sigma and Pi Bonding

2. Two S orbitals overlap
Sigma Bond ơ

3. Two px orbitals overlap
Sigma Bond

4. Sigma Bonds are sausage shaped They occur when Two s orbitals overlap
Two Px orbitals overlap
Head on

5. As the two px orbitals overlap so do the two py orbitals if they are occupied

6. 
Py or Pz orbital
Py or Pz orbital
Pi Bond

7. Pi Bonds As the 2 x orbitals join [forming a sigma bond]
The y orbitals overlap [if they are occupied]
They also form a modified electron cloud.
Shaped vaguely like the symbol π

8. Pi Bonds are shaped like the symbol  Twp Py orbitals overlap
Occur when
Twp Py orbitals overlap
Two Pz orbitals overlap
side on

9. Bond Construction Single bonds are Sigma bonds
Double bonds consist of one Sigma bond and one Pi Bond
Triple bonds consist of one Sigma Bond and two Pi Bonds