1. Tilldela kända oxidationsnummer:

* Väte (H): +1 (nästan alltid)

* Syre (O): -2 (förutom i peroxider)

* Mangan (Mn): +7 (i permanganatjon, MnO4⁻)

2. Ställ in en ekvation:

Since the compound is neutral, the sum of the oxidation numbers of all the atoms must equal zero. Let 'x' represent the oxidation number of nitrogen:

(1 * 4) + (x) + (+7) + (-2 * 4) =0

3. Lös för x:

* 4 + x + 7 - 8 =0

* x + 3 =0

* x =-3

Therefore, the oxidation number of nitrogen (N) in NH₄MnO₄ is -3.