Atoms are the fundamental building blocks of all matter. This is the basis of chemistry. But if they are the bricks, then what is the mortar? What holds the atoms together to form molecules? The answer is "bonds" which, of course, doesn't really explain anything because it raises the next question--what is a bond? It is the nature of science that the answer to one question invariably leads to another question.

A simple thought experiment can be used to determine the basic nature of bonds. Electrostatics tells us that oppositely charged particles attract and that similarly charged particles repel. This means that nuclei will repel each other, as will electrons. Simply trying to push two nuclei together will not allow for the formation of a molecule. But attractions do exist between electrons and nuclei and this tends to favor molecule formation. Here's what happens...