How might you predict whether a compound is ionic or covalent simply by looking at its formula?

Answer 1

In general, a metal bonded to a nonmetal is an ionic bond. A nonmetal bonded to a nonmetal is a covalent bond. Technically, the greater the differences of electronegativities, the more ionic the bond is. The only exception is when a metal is pure or bonded to another metal, the bond is a metallic bond.