Rules for Naming Binary Compounds

Covalent Compounds (Molecular Compounds)Ionic Compounds

BINARY IONIC COMPOUNDS are formed between a metal and a nonmetal.

1. The charge on an ion is referred to as the oxidation number of that element. when it is an ion.

2. Metallic elements lose electrons (forming positive ions).

For example, a. the oxidation number of alkali metals (Li, Na, K, etc.) is always +1 in a

compound. b. The oxidation number of alkaline earth metals (Be, Mg, Ca, etc.) is always

+2 in a compound. c. Silver ions always have a +1 charge. Zinc and cadmium ions always have a

+2 charge. Aluminum ions always have a +3 charge. d. Most other metals can have more than one oxidation number in a compound.

3. Nonmetals gain electrons (forming negative ions).

For example, a. an oxide ion always has a charge of -2. b. A nitride ion always has a charge of -3. c. Halogens (chloride, etc.) are always -1.

Binary covalent (binary molecular) Compounds