1. Assign Oxidation States to Oxygen

* Oxygen usually has an oxidation state of -2.

* Since there are four oxygen atoms, their total contribution is -8.

2. Consider the Overall Charge

* The phosphate ion (PO₄⁻³) has a charge of -3.

3. Solve for Phosphorus

* Let 'x' represent the oxidation state of phosphorus.

* The sum of the oxidation states must equal the overall charge:

x + (-8) = -3

4. Calculate the Oxidation State of Phosphorus

* Solve for 'x':

x = -3 + 8

x = +5

Therefore, the oxidation state of an individual phosphorus atom in PO₄⁻³ is +5.