- (F, T) The oxidation state of oxygen in most situations is −2. The oxidation
state of Mn in MnO 4 − then would be +7 because the addition of the oxidation
states in polyatomic ions must equal the overall charge of the ion.
state of Mn in MnO 4 − then would be +7 because the addition of the oxidation
states in polyatomic ions must equal the overall charge of the ion.