The formula of the compound formed by Iron (ii) ions and chromate ions is FeCrO₄
Explanation:
Iron (ii) ions, Fe²⁺ have a positive charge of +2. Chromate ions, CrO₄²⁻, on the other hand have a positive charge of -2. When iron (ii) ions and chromate ions combine two form a compound, each ion will contribute a mole of ion towards the formation of the compound. This is in line with the idea that a compound carries no charge. The positive charge (+2) of the iron (ii) ions are balanced by the negative charge of the chromate ions as shown mathematically as follows;
+2 + (-2) = 0; i.e. Fe²⁺ + CrO₄²⁻ = FeCrO₄
Therefore, the formula of the compound formed by Iron (ii) ions and chromate ions is FeCrO₄