Learn all about molecular structures in this easy-to-understand, audio book. See how valence electrons determine how atoms bond together, and look at the bonding inside some of the most common molecules around you.

Take an interactive quiz over DNA. After completing the quiz, check your score, and then revisit any incorrect question for further review.

[Free Registration/Login may be required to access all resource tools.] Atoms and how they are related to elements, and the particles that make up atoms.