The formula of has to be given.
In the formula of the compound, the sum of the charge of cation and anion must be equal to zero. The ratio of cation and anion to be known in order to arrive the formula of a compound.
Rules for Nomenclature of ionic compounds:
The name of the cation is followed by the name of the anion.
Polyatomic ions: Ions that consist of a combination of two or more atoms.
Polyprotic ions: It contains more than one ionizable hydrogen atom
Oxoacids: Acids when dissolved in water produce hydrogen ions and the corresponding oxoanion.
Oxoanions: Anions that contain one or more than one oxygen atoms with different element at the center.
Naming rules of Oxoanions:
In order to apply the following rules, the formulae and charge of the Oxoanions whose names end in to be known.