Chemists name a compound according to the atoms and bonds that compose it. To name a binary ionic compound, simply write the name of the cation followed by the name of the anion. To name a monatomic anion, you need to replace the suffix of the element name with the suffix –ide.

(cation) (anion) EXAMPLE: AlO 3 Aluminum oxide

Iron, for example, can form cations with charges +2 or +3. To distinguish the different cations of a transition metal, chemists add Roman numerals to the element name. Thus, Fe +2 is named iron (II) and Fe +3 is named iron (III). These names are read as “iron two” and “iron three”.

(cation) (anion) EXAMPLE: FeO 3 Iron (III) oxide

1. NaCl

2. Fe 2 S 3

1. BaCl 2

5. CuBr 2

7. Zn 3 (PO 4 ) 2