* Chlorine (Cl) is more electronegative than nitrogen (N). This means chlorine will have a negative oxidation number.
* The overall charge of the molecule is zero. This means the sum of the oxidation numbers of all the atoms in the molecule must equal zero.
Here's the breakdown:
1. Chlorine (Cl) usually has an oxidation number of -1. Since there are three chlorine atoms in NCl₃, the total oxidation number contributed by chlorine is -3.
2. To balance this, the nitrogen (N) must have an oxidation number of +3.
Therefore, the oxidation number of nitrogen (N) in NCl₃ is +3.
