Rewrite the formulas of the substances and indicate the valence of sulfur: SO2 SO3

In sulfur oxides SO2 and SO3, oxygen has a valence of -2. SO2 – sulfur dioxide. Since the molecule of this oxide has two oxygen atoms and one sulfur atom, the sulfur valency is +4. Thus SO2 is also called sulfur oxide IV. SO3 is sulfuric gas. Since there are three oxygen atoms and one sulfur atom in the molecule of this oxide, the valence of sulfur is +6. Thus SO3 is also called sulfur oxide VI.