How are these questions tested in the A level syllabus? There
seems to be little emphasis on this section of the notes and
tutorials.
If you're asking literally "what kind of qns do they ask about
alkyl halides", then your answer lies in the TYS.
If you're asking for advice on how to approach alkyl halides,
then :
Appreciate that alkyl halides are electrophiles (girls), because
they have very good leaving groups (old boyfriends), and hence can
be attacked by nucleophiles (new boyfriends).
Halogens are good leaving groups because halide ions are stable,
because they have low anionic charge densities. The only exception,
of course, is F : F is a poor leaving group because F- has a high
anionic charge density. Additionally the C-F bond dissociation
enthalpy is significantly more endothermic than the other C-X
bond dissociation enthalpies.
On this topic, you should also appreciate how the two factors
"sterics" and "electronics" collectively determine why primary
alkyl halides undergo SN2, why tertiary alkyl halides undergo SN1,
and why secondary alkyl halides undergo both.