The oxidation state of bromine in Br2 is 0. This is because Br2 is a diatomic molecule, meaning it consists of two identical atoms of bromine sharing a covalent bond. In a covalent bond, the two atoms are considered to "share" their valence electrons equally, resulting in a net charge of 0 for each atom. Therefore, the oxidation state of each bromine atom in Br2 is 0.
