NH4NO3 is composed of two ions: the ammonium ion NH4+ and the nitrate ion NO3- . To determine the oxidation state of the nitrogen atom in NH4NO3, we need to look at the oxidation states of nitrogen in both ions separately.1. In the ammonium ion NH4+ , nitrogen is bonded to four hydrogen atoms. Hydrogen has an oxidation state of +1. Therefore, the oxidation state of nitrogen in NH4+ is -3 to balance the total charge of +1.2. In the nitrate ion NO3- , nitrogen is bonded to three oxygen atoms. Oxygen has an oxidation state of -2. The total oxidation state of the three oxygen atoms is -6. To balance the total charge of -1, the oxidation state of nitrogen in NO3- is +5.So, the nitrogen atom has two different oxidation states in NH4NO3: -3 in the ammonium ion and +5 in the nitrate ion.