Is it worth resitting any chem units for an A, AQA?

I'm on 237 UMS and need 240 UMS for an A.
CHEM1 mark: 85/100 = A
CHEM2 mark: 107/140 = B (think it was 112 or something for an A)
EMPA: 42/60 = B, (worth 20%)

CHEM1 seems to be the easiest to retake but I haven't looked at that stuff since ages and I'm worried they'll make it REALLY hard like they tend to do usually. Not sure what went wrong with CHEM2, found it easy, found module content fine, but I obviously did screw up somewhere to get a B rather than the A I was predicted. Should I just focus on CHEM4/CHEM5 or should I retake one of these units? I'll have 6 exams in June (not including these possible chemistry resits),

If I were in your position, I would think about re-taking CHEM2 - you have the potential to gain up to 33 UMS, which would be a big boost to your overall score for the A level. Also, CHEM2 does contain some similar content with CHEM4, in terms of curly-arrow mechanisms, and bits of physical chemistry, so going over CHEM2 may help you get a better grasp of the content of CHEM4, and vice versa.

However, I think you should speak to your teachers and/or head of department before making any such decisions, in order to get their input on re-taking too.

yeah I think you're right, I will resit CHEM2 and hopefully revision shouldn't be difficult this time round. Is it worth revising lightly at the moment like one past paper a week? I know I have around 9 months left but those mechanisms were a NIGHTMARE to learn before, and I really can't afford to forget them! Thanks