Three Bond Types

Here we see the three types of molecular bonds. The first, ionic, is when one atom gives up an electron to another, so they both have an outer shell with eight electrons.

The seccond one is a covalent bond, where two or more atoms share valence electrons, so that they have a collective outer shell of eight electrons.

And the third is when one electron infiltrates another atom, beats the everloving crap out of the nucleus, and steals all the electrons back to its atom, forcing the other atom to stick to it.