(i) Draw diagrams to show how sigma (σ) and pi (π) bonds are formed between atoms.

(ii) State the number of sigma (σ) and pi (π) bonds in propane and propene.

Construct the mechanism of the formation of 2-bromopropane from hydrogen bromide and propene using curly arrows to denote the movement of electrons.

i

ii

Award [1] for two or three correct answers.
Award [2] for all four correct.

curly arrow going from C=C to H of HBr and curly arrow showing Br leaving
representation of carbocation
curly arrow going from lone pair/negative charge on Br^– to C⁺

Award [2 max] for formation of 1-bromopropane.