The inorganic compound formed by the combination of sodium and chlorine atoms is sodium chloride NaCl . This compound is ionic in nature. The reason for this is that sodium Na is a metal from Group 1 of the periodic table, and chlorine Cl is a non-metal from Group 17. Sodium has one electron in its outermost shell, while chlorine has seven electrons in its outermost shell. In order to achieve a stable electron configuration, sodium loses its one valence electron, forming a positively charged ion Na+ , and chlorine gains one electron, forming a negatively charged ion Cl- . The electrostatic attraction between these oppositely charged ions results in the formation of an ionic bond, creating the ionic compound sodium chloride NaCl .