It's a good idea, to know a lot more than nothing about the periodic table. Notice the ionization energy trends, know electron affinity trends, certainly know the annotation used, i.e. atomic number, atomic mass, etc.It's also a good idea to memorize the weights of things like O, C, N, H, and a few others. You'll notice as you do calculations that it helps not having to look them up. I saw some hardcore chemist know the entire thing, but that's a bit much for beginners. It would be better to concentrate on thermodynamics, ion naming, etc.Think of the periodic table as a huge cheat sheet. The more you memorize, the more cheating you can do. There are so many things for which you will go back to the table. Certainly, however, know trends involving electron affinity and ionization energy, and how the octet rule for electron configuration is patterned for each group.