Final answer:
Sulfur has an oxidation state of +4 in the compound sulfur dioxide (SO₂). This is determined by assigning oxygen an oxidation number of -2 and balancing the overall charge to zero.
Step-by-step explanation:
In chemistry, sulfur can exhibit different oxidation states in various compounds. The oxidation state is not an actual charge on the atom but a useful accounting tool for keeping track of electrons during chemical reactions. For sulfur to have an oxidation state of +4, we can look at the molecule SO₂ (sulfur dioxide). When assigning oxidation numbers to the atoms in SO₂, we follow the rule that the sum of the oxidation numbers must equal the charge on the species, which is zero for neutral molecules. Since each oxygen contributes an oxidation state of −2, the two oxygen atoms together contribute −4, which means sulfur must have an oxidation state of +4 to balance this out and make the sum of oxidation numbers equal zero.