As part of my writing for prospective chemistry undergraduates, I've been writing a list of chemistry topics you'll probably need to understand for university, which should have covered at school. We all miss bits and pieces, and some of us miss a lot, and I thought the list might help identify any essential knowledge that's missing. But it's not just what's missing that needs fixing...
Perhaps surprisingly, there are a few things that A-level chemistry teaches you that are neither true nor useful at university level.
Some university lecturers (mentioning no names) get agitated about lies-to-children in A-level chemistry and may make disparaging remarks about "planet A-level" and so on.
I think their stance is understandable but a somewhat condescending, and they can be overzealous about it. I can't think of a way to teach chemistry at school without making some compromises between correctness and simplicity.