Chemical bonds form by the attraction the electrons of one atom to the proton of another atom. Common types of bonds include ionic, covalent and metallic bonds. The formation of the bond links the two atoms through the strong attractive forces, using a bond, a region where the electrons of the atoms interact with one another.
The electrons taking part in chemical bonds are the valence electrons. These are the electrons in the outer shell of electron orbitals. While electrons themselves repel one another, the force of the proton is great enough to overcome the resistance to form the bond, according to About.com.
In ionic bonds, one atom donates its valence electrons to another atom in the formation of the bond. Covalent bonds form when atoms are able to share valence electrons. However, if the attraction for electrons is greater in one atom than the other, the electrons tend to orbit the stronger atom. As a result, the molecule tends to have a positive end and a negative end and the bond is a polar covalent bond. Water forms polar molecules. Metal atoms join together through metallic bonds. In these bonds, any of the metal atoms within a region has the ability to share the electrons.