So if you really want to understand atoms, you need to understand how atoms interact with other atoms. In physics, we describe the interaction between two objects in terms of forces. But remember that the strong force has a very short range. It has no effect on electrons, and in fact, it has no effect outside the nucleus. And that means that we have to look again at the electric charge in atoms.
Covalent bonds Let's start out with a relatively simple case.
That of two hydrogen atoms. Each of these has one electron, which quorbits a nucleus consisting of just one proton. Typically, the electron is in its lowest possible energy state, that is, its ground state. The electron in each atom starts to notice the proton of the other atom. As a result, it becomes attracted not only to its own proton, but to the proton of the other atom as well.