This document discusses ionic bonding and the formation of ions. Valence electrons are involved in chemical bonding and can be lost or gained to achieve a noble gas configuration. Ionic bonding occurs when a metal atom donates its valence electron to a nonmetal atom, forming cations and anions that are attracted due to opposite charges. Sodium and chlorine are used as an example, with sodium donating an electron to chlorine to form sodium and chloride ions. The ions crystallize to form sodium chloride. Ions can be separated by solvents with partial charges and reform when the solvent evaporates. The type of ion formed depends on an element's valence electrons and what is needed to achieve a noble gas configuration.