I’ve forgotten gcse chemistry content and im taking it at alevelsWatch this thread
I'm sure you'll be alright good luck
electrolysis is acc quite confusing
but just spend a couple of hours tomoz on it and u should b ok
But as said, if you're worried, do the recap work! Equally get in touch with your teacher - likely lots of pupils are in the same situation and you might get offered some extra catch up work. Don't worry if the prep work takes you ages at the moment - make sure you're doing it properly and looking up what you don't know and it'll be a good recap.
A levels is a huge step up from GCSE's.