Here's how to determine the oxidation state of sulfur (S) in the sulfite ion (SO₃⁻²):

1. Assign Oxidation States to Oxygen:

* Oxygen typically has an oxidation state of -2, except in peroxides and when bonded to fluorine.

2. Use the Overall Charge of the Ion:

* The sulfite ion has a charge of -2.

3. Set Up an Equation:

Let x be the oxidation state of sulfur:

x + 3(-2) = -2

4. Solve for x:

x - 6 = -2

x = +4

Therefore, the oxidation state of sulfur (S) in SO₃⁻² is +4.