# How do you find the oxidation number of one element?

Aug 26, 2016

The oxidation number of an element is generally $0$.

#### Explanation:

Oxidation state is formally the charge on an atom when it donates or accepts electrons. While this is a formal exercise it does have utility in the balancing of redox equations. Because elements have demonstrably not transferred electrons, they are assigned a $0$ oxidation state; they are $\text{zerovalent}$.

The burning of coal and fossil fuels is certainly an example of a redox equation:

$\text{Coal is oxidized from 0 to +IV}$

$C \rightarrow {C}^{+ I V} + 4 {e}^{-}$

$\text{Oxygen is reduced from 0 to -II}$

${O}_{2} + 4 {e}^{-} \rightarrow 2 {O}^{2 -}$

For both these redox equations mass and charge are balanced, as they must be. (Are they?)

Add them together to eliminate the electrons:

$C \left(s\right) + {O}_{2} \left(g\right) \rightarrow C {O}_{2} \left(g\right)$

Both elemental reactants are zerovalent BEFORE electron transfer occurs.