What is the chemical formula for sulfite?

The chemical formula for sulfite is represented as SO3(2-). This formula indicates that it consists of one sulfur atom and three oxygen atoms, and it carries a -2 charge overall. Sulfite is a polyatomic ion, which means it is an ion made up of multiple atoms bonded together. In this case, the sulfur atom is surrounded by three oxygen atoms, and because of the way the atoms combine and the total number of valence electrons involved, the compound holds a negative two charge.

The other options represent different polyatomic ions. For example, SO4(2-) denotes sulfate, which contains one sulfur atom and four oxygen atoms, with also a -2 charge. S2O3(2-) is the formula for thiosulfate, a different polyatomic ion that includes two sulfur atoms and three oxygen atoms, still maintaining a -2 charge. Lastly, CrO4(2-) is the formula for chromate, which involves chromium and oxygen and is unrelated to sulfite.

Understanding the structure and composition of these polyatomic ions helps with deducing their chemical formulas accurately. In the case of sulfite, focusing on the number of oxygen atoms relative to the sulfur gives clarity to its representation as SO3(