# How do you determine oxidation states of elements?

The oxidation state of an element is generally $0$
Oxidation/reduction reactions are characterized by the formal loss or gain of electrons. An element is zerovalent, and electron transfer is presumed to occur after reaction. The reactants in the following redox process certainly are oxidation state $0$:
$C \left(s\right) + {O}_{2} \left(g\right) \rightarrow C {O}_{2} \left(g\right)$