1. Assign Oxidation Numbers to Oxygen:
* Oxygen usually has an oxidation number of -2, except in peroxides (where it's -1) and when combined with fluorine (where it's positive).
2. Set Up an Equation:
* Let 'x' be the oxidation number of arsenic.
* The overall charge of the compound is zero.
* The equation is: 2x + 5(-2) = 0
3. Solve for 'x':
* 2x - 10 = 0
* 2x = 10
* x = +5
Therefore, the oxidation number of arsenic (As) in As₂O₅ is +5.
