* Mercury(I) oxide (Mercurous oxide):
* Formula: Hg₂O
* Explanation: Mercury(I) ions have a +1 charge (Hg⁺). Oxygen has a -2 charge (O⁻²). To balance the charges, you need two mercury(I) ions for every oxygen atom.
* Mercury(II) oxide (Mercuric oxide):
* Formula: HgO
* Explanation: Mercury(II) ions have a +2 charge (Hg²⁺). Oxygen has a -2 charge (O⁻²). The charges are already balanced, so you need one mercury(II) ion for every oxygen atom.