The atoms of most elements form chemical bonds because the atoms become more stable when bonded together. Electric forces attract neighboring atoms to each other, making them stick together. Strongly attractive atoms seldom spend much time by themselves; before too long, other atoms bond to them. The arrangement of an atom’s electrons determines how strongly it seeks to bond with other atoms.
Atoms, Electrons and Potential Energy
In atoms, electrons are arranged into complex layers called shells. For most atoms, the outermost shell is incomplete, and the atom shares electrons with other atoms to fill the shell. Atoms with incomplete shells are said to have high potential energy; atoms whose outer shells are full have low potential energy. In nature, objects with high potential energy “seek” a lower energy, becoming more stable as a result. Atoms form chemical bonds to achieve lower potential energy.
The elements belonging to the noble gases group, including neon and helium, have atoms with full outer shells and rarely form chemical bonds. Because their shells are complete, these atoms already have very low potential energy and little power to attract other atoms. They bump into other atoms all the time but almost never form bonds.