Drawing the Structure of Organic Molecules - Although larger molecules may look complicated, they can be easily understood by breaking them down and looking at their smaller components, All atoms want to have their valence shell full, a"closed shell." Hydrogen wants to have 2 e whereas carbon, oxygen, and nitrogen want to have 8 e When looking at the different representations of molecules, keep in mind the octet Rule. Also remember that hydrogen has one bond, oxygen has two bonds, nitrogen has three bonds, and carbon has four bonds.