Ionic bonding occurs as a result of an electron exchange. Most atomic nuclei do not posses a stable electronic configuration in their outer orbits; they either have an excess or deficiency. Those with an excess are likely to combine with those with a deficiency so that both atoms have a more stable configuration. However, in moving an electron from one to the other, both atoms become electrically charged, each forming an ion -- One becomes positive, and the other becomes negative. These opposing charges attract, and keep the atoms together, forming a compound.