The oxidation number is used in assigning the charged state of elements in any compound, ions and molecules. It can also indicate the state of oxidation of any element in a chemical compound.
The oxidation state of elements varies depending on the nature of the compound. We can acquire that by inspection and/or algebraic method.
For `Pb_3O_4` , there are series of assumptions:
-the net charge is zero (neutral compound).
-The oxidation number of O is always -2 (unless otherwise stated)
-the oxidation number of Pb is unknown (x).
The algebraic expression can be written as:
`3(x) + 4 (-2) = 0`
- 3 = number of Pb atoms
- 4 = number of O atoms
- -2 = charge of O atom
- 0 = net charge
`3x + (-8) = 0`
`x = 8/3`
Having a fraction answer for the oxidation state is rare but possible.