- 1). Determine if a compound is covalent of ionic in nature. Covalent compounds form from non-metal atoms. Compounds that are ionic compounds form from a metal ion and a non-metal ion.
- 2). Count the number of different elements in the ionic compound. If the number of different element atoms in the compound doesn't exceed two, the compound is a binary ionic compound. Ionic compounds containing more than three different elements are ionic compounds that possess a polyatomic ion. For example, sodium chloride contains two elements and is a binary ionic pair, whereas sodium carbonate contains three elements and contains a polyatomic ion with carbon and oxygen making up the polyatomic ion.
- 3). Examine the name of the compound. Compounds that end in --ate and --ite are always polyatomic ions. If the compound ends in --ide and only contains two elements, the ionic compound is a binary ionic pair like sodium chloride. Sodium hydroxide ends in --ide but has three elements in the compound so it must possess a polyatomic ion.
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