What is the charge of the carbonate ion?

The carbonate ion, which has the chemical formula CO₃²⁻, carries a charge of -2. This can be understood by examining the structure and the oxidation states of the elements involved.

In the carbonate ion, carbon has an oxidation state of +4, while each oxygen atom typically has an oxidation state of -2. Given that there are three oxygen atoms, the total contribution from the oxygen is -6. To balance the total charge of the ion to reflect its overall -2 charge, the carbon must therefore have a +4 oxidation state. When you add up the contributions from each atom (one +4 from carbon and three -2 from oxygen), you obtain a net charge of -2, confirming the charge of the carbonate ion.

Recognizing the typical charges of common polyatomic ions is important for solving related problems in chemistry, especially in the context of chemical reactions and compound formation.