What is the oxidation number of nitrogen in nitrogen gas #N_2#?
Oxidation number is the charge left on the central atom, when the bonding electrons are broken with the charge assigned to the most electronegative atom.
For homonuclear diatomic molecules, i.e. dinitrogen, dioxygen, dihalogen, of course the atoms have equal electronegativities, and the charge is conceived to be shared.
At any rate, the formal oxidation number of