What is the chemical formula for chromate?

The chemical formula for chromate is represented as CrO4(2-). This indicates that the compound consists of one chromium (Cr) atom and four oxygen (O) atoms, with an overall charge of -2. Chromate is a polyatomic ion that plays an important role in various chemical reactions, particularly in oxidation-reduction processes and in analytical chemistry.

Understanding the structure of chromate is essential; the oxidation state of chromium in chromate is +6, which is a key characteristic for its reactivity and its applications. The tetrahedral arrangement of the four oxygen atoms around the chromium atom contributes to the stability and properties of chromate.

Other options may represent different anions or oxidation states of chromium and oxygen, but they do not correctly describe the chromate ion, which specifically requires four oxygen atoms combining with a single chromium atom to give the correct formula and charge. Therefore, B is the accurate representation of the chromate ion.