To find the formula of an ionic compound first identify the cation and write down its symbol and charge. Keep in mind however that the formula for an ionic compound does not represent the composition of a discrete molecule so it may not correctly be referred to as the molecular mass As an example consider sodium chloride NaCl the chemical name for common table salt. You can often recognize ionic compounds because of their properties.
Finally combine the two ions to form an electrically neutral compound.
Here are some examples. Ii The cation aluminum ion is. Ionic compounds form when positive and negative ions share electrons and form an ionic bondThe strong attraction between positive and negative ions often produce. You can often recognize ionic compounds because of their properties.