NH4NO3 is composed of two ions: NH4+ ammonium and NO3- nitrate . To find the oxidation state of nitrogen in NH4NO3, we need to determine the oxidation state of nitrogen in each ion separately.In the NH4+ ion, nitrogen is bonded to four hydrogen atoms. Hydrogen has an oxidation state of +1. Therefore, the oxidation state of nitrogen in NH4+ is -3 since +1 * 4 = +4, and the overall charge of the ion is +1, nitrogen must have an oxidation state of -3 to balance the charge .In the NO3- ion, nitrogen is bonded to three oxygen atoms. Oxygen has an oxidation state of -2. Therefore, the oxidation state of nitrogen in NO3- is +5 since -2 * 3 = -6, and the overall charge of the ion is -1, nitrogen must have an oxidation state of +5 to balance the charge .So, in NH4NO3, nitrogen has two different oxidation states: -3 in the NH4+ ion and +5 in the NO3- ion.