Generally, if you know the answer to a question, it can be relatively easy to write an explanation either by writing a few sentences, drawing a diagram or by producing an example.
You probably know by now (through your studies of chemistry) that electrons are the “magic” behind chemical reactions. They do all the hard work - moving here, moving there, joining this atom, leaving that atom, forming bonds, etc.
Mathematics is built on laws. No matter what your opinion on if the laws are stupid or not, you’re going to have to do what they tell you if you want to pass your GCSE.
We all know that exam-time is stressful. There’s all that information to retain, and some of us are just no good at that, right?