Question

What are the oxidation states of the atoms in a diatomic gas?

Answer 1

If it is elemental gas, the oxidation number is `0`.

Explanation:

The oxidation number of an atom in a chemical bond, is the charge left on the atom of interest when all the bonding pairs of electrons are broken, with the charge devolving to the most electronegative atom.

When we do this for `H_2`, or `X_2`, or `N-=N`, or `O=O`, we get sharing of electrons, and a `0` oxidation state. Of course, if it is a diatomic gas such as `H-Cl`, we break the bond and the electronic charge is distributed to the most electronegative atom, here the halide, i.e. `H^(I+)` and `Cl^(-I)`. With an interhalogen, say `Br-Cl`, we get `Br^(I+)` and `Cl^(-I)`