Ammonium nitrate NH4NO3 consists of two ions: the ammonium ion NH4+ and the nitrate ion NO3- . To determine the oxidation state of nitrogen in NH4NO3, we need to find the oxidation state of nitrogen in each ion separately.1. In the ammonium ion NH4+ :Hydrogen has an oxidation state of +1. Since there are four hydrogen atoms, the total positive charge from hydrogen is +4. To balance the overall charge of the ion, the oxidation state of nitrogen N in NH4+ must be -3.2. In the nitrate ion NO3- :Oxygen has an oxidation state of -2. Since there are three oxygen atoms, the total negative charge from oxygen is -6. To balance the overall charge of the ion, the oxidation state of nitrogen N in NO3- must be +5.So, in NH4NO3, nitrogen has two different oxidation states: -3 in the ammonium ion NH4+ and +5 in the nitrate ion NO3- .