In potassium nitrate (KNO3), the oxidation state of the individual nitrogen atom can be determined by considering the known oxidation states of the other elements in the compound and applying the principle of charge balance.
The potassium ion (K+) has a known oxidation state of +1 because it belongs to Group 1 of the periodic table, which typically loses one electron to form a positive ion.
The oxygen atoms in nitrate (NO3-) ions have a combined oxidation state of -2 because oxygen usually has an oxidation state of -2 in compounds.
To find the oxidation state of nitrogen (N), we can set up an equation based on the overall charge neutrality of the compound:
(+1) + N + (3 × -2) = 0
Simplifying the equation:
+1 + N - 6 = 0
N - 5 = 0
N = +5
Therefore, in KNO3, the individual nitrogen atom has an oxidation state of +5.