1. Assign Known Oxidation States:
* Oxygen (O): Oxygen usually has an oxidation state of -2.
* Overall Charge: The polyatomic ion has a charge of -4.
2. Set Up an Equation:
Let 'x' represent the oxidation state of vanadium. Since there are two vanadium atoms in the ion, we'll use 2x.
The equation will be: 2x + (7 * -2) = -4
3. Solve for 'x':
* 2x - 14 = -4
* 2x = 10
* x = 5
Therefore, the oxidation state of vanadium (V) in V₂O₇⁴⁻ is +5.
