Also, you’re always allowed to have the periodic table with you at chemistry exams. In 5 years in the chemistry department I only ever memorized H-He-Li-Be-B-C-N-O-F and I roughly know where Mg and Na and Cl are from having to look them up often enough, but at exams you are allowed to bring it, or it’s handed out if you really need it, and it’s often on a poster in the background anyway, or printed as decoration on your coffee mug or the back of the free T-shirt the person in front of you is wearing.