Which best explains how elements combine in different ways to produce compounds?

There are two kinds that describes how elements combine to form a chemical compound: one is ionic bond and the other is covalent bond. Ionic bond occurs when metals are combined with nonmetals. The newly formed substance or compound is composed of a positive and negative ions produced by adding/subtracting electrons from neutral atoms and molecules. On the other hand, covalent bond occurs when two nonmetals combine.