It is the electrons moving between the metal atoms but its more to do with how metals are structured. Basically you can think of it as layers of atoms with free electrons moving around. Metals can be molded because these layers can slide around each other, so the entire metal can be made into a different shape.
There is a rule in naming polyatomic anions containing oxygen.
Those names ending in <em>–ate</em> are given to the most common oxyanion of an element.
While those names ending in <em>–ite</em> are for those that contains fewer O atom for
the same charge. Since P has fewer O atoms, its name ends in <em>–ite</em>.
Thus, P is phosphite while P is phosphate.