What charge does the sulfite ion carry?

The sulfite ion has a charge of -2, which corresponds to the correct answer. Sulfite is a polyatomic ion comprised of sulfur and oxygen, and its molecular formula is SO₃²⁻. In this ion, sulfur is bonded to three oxygen atoms, and the overall charge of -2 suggests that the ion has gained two additional electrons compared to the number of protons in the sulfur atom.

This charge can be understood by considering the typical oxidation states of sulfur and oxygen in compounds. Oxygen generally has an oxidation state of -2. In the case of sulfite, with three oxygen atoms, the total negative charge contributed by the oxygens is 3 × (-2) = -6. To balance this and result in an overall charge of -2 for the ion, sulfur must have an oxidation state of +4. Therefore, the charge of the sulfite ion is indeed -2.

Other options do not accurately reflect the composition or stability of the sulfite ion. A charge of -3 would imply an incorrect balance of electrons and protons, -1 doesn't correspond to the common knowledge of sulfite, and a charge of 0 would indicate a neutral molecule without any net charge, which does not apply