ocr: Halogens (Group YIIA or 17) have an oxidation number of -11 Clin HC1, -1 unless they are combined with an element of higher Clin HOCI, +1 electronegativity (generally oxygen). Ina neutral molecule, the sum of oxidation numbers is 0. In a polyatomic ion, the sum of the oxidation numbers present is equal tot the total charge on the ion.
