Synthesis of Aromatic Molecules (U2, c4/6)

Question 1

What is the molecular formula of benzene?

Answer 1

C6H6

Question 2

How are the σ bonds formed in a benzene ring?

Answer 2

Each carbon is sp2 hybridised,

and the THREE filled sp2 orbitals form the σ bonds with ONE hydrogen atom and TWO neighbouring carbon atoms.

Question 3

How are the π bonds formed in a benzene ring?

Answer 3

There is an electron left in a p orbital on each carbon atom,
and each p orbital overlaps with the TWO p orbitals on either side, forming a π molecular orbital.

Question 4

In a benzene ring, why are the six electrons in the π orbital known as “delocalised electrons”?

Answer 4

The electrons are not tied to any one of the carbon atoms - they are shared by all six.

Question 5

What gives benzene an unusual stability?

Answer 5

Its delocalised electrons.