Go over notes in a study group. If you are skipping class and depending on others for notes, you could be hurting yourself immeasurably. Then, you need to go back and work on that topic. It is important for an understanding of how bonds form and molecules work, and it will be on the comprehensive final. The summary at the end of each chapter in the book can be very helpful here.
Science is more than terminology.
Organizing your notes may be very helpful here. Doing this will ensure that you come to an understanding of what you missed and why you missed it. Have confidence in your knowledge. Go with the knowledge you have, use your knowledge to work out questions that you are not certain of, and use that knowledge to think through difficult questions. Harvard Medical School researchers, led by assistant professor of psychiatry Robert Stickgold, found that people who slept after learning and practicing a new task remembered more about it the next day than people who stayed up all night after learning the same thing.