* Oxygen's Oxidation Number: Oxygen usually has an oxidation number of -2.
* Neutral Compound: Bi₂O₃ is a neutral compound, meaning the sum of the oxidation numbers of all the atoms must equal zero.
Calculation:
1. Oxygen's Total Oxidation Number: There are three oxygen atoms, each with a -2 charge, for a total of -6.
2. Bismuth's Total Oxidation Number: To balance the -6 charge from oxygen, the two bismuth atoms must have a total of +6.
3. Bismuth's Oxidation Number per Atom: Since there are two bismuth atoms, each bismuth atom has an oxidation number of +3.
Therefore, the oxidation number of bismuth (Bi) in Bi₂O₃ is +3.
