1. Draw the VESPR structures for
14.1.1
Include bond angles, names of
shapes

2. Bonding AHL
• Describe sigma and pi bonds
• Explain hybridization in terms of sp sp2 sp3
• Explain relationship between Lewis
structure, shape and hybridisation

3. Sigma Bonds
• Sigma bonds are all single bonds, and result
from axial overlap of orbitals.

4. π Bonds
• Result from sideways overlap of parallel
porbitals

5. Basics
• A single bond is a SIGMA bond
• A double bond is ONE SIGMA ONE PI
• A triple bond is ONE SIGMA TWO PI

6. Hybridisation – sp3

7. Hybridisation – sp2

8. Hybridisation - sp

9. Homework Task
• Using the following molecules create a
student help sheet to explain the bonding, the
shape, the hybridisation, and number of sigma
and pi bonds.
• In Carbon Dioxide, Methane and Propene.

10. Geometry and Hybridisation
• All you have to do is count the negative
centres, and don’t forget lone pairs
• Inorganic :
• 4 negative centres is sp3, e.g. NF3 ( 3bp 1nbp in this case )
• 3 negative centres is sp2, e.g. BF3 ( 3bp in this case )
• 2 negative centres if sp
• Organic :
• sp3 is Td 109.5, e.g. Alkanes
• sp2 is Trig Pl 120, e.g. Alkenes, Carbonyl groups
• sp is lin 180, e.g. Alkynes

11. Starter
• Explain how sp2 hybridization arises 
• Use electrons in boxes notation to explain
your answer.

12. When electron pairs are not confined
to two adjacent bonding atoms but
extend over 3 or more atoms

13. Benzene Facts 
• Planar regular hexagon
• All bond angles 120 degrees
• Bond lengths intermediate between single and
double bonds
• Reluctant to undergo addition reactions.

14. Nitrate Ion

15. Nitrite Ion Resonance Structures ?

16. Carbonate Anion

17. Ozone

18. Ethanoate

19. Learning Check 
• N01/420/H(2) part (a) ONLY