Valence stability determines the chemical reactivity of an element. Generally, an atom with 8 valence electrons is most stable. For example, metals with 1 valence electron will readily give up that electron to another atom in need of it. An atom with 7 valence electrons will be able to take the electron of another atom. The ions created will allow bonds to be formed: covalent bonds, ionic bonds, polar bonds, and probably others as well. The type of element, its electronegativity, and valence level are only a few factors of the number of bonds certain elements can form.
