Answer: Chlorine is losing electrons and being oxidized.
Justification:
1) Chlorine is losing electrons
As you se the side of the products shwo two electrons, that means that those electons were lost by the reactants. Given that the only reactant is chlorine, it is releasing or losing those electrons.
2) Chlorine is being oxidized.
The substance that loses electrons and, hence, increases its oxidation number, is the substance being oxidized.
In this case Cl (-) in the side of the reactants has oxidation state (1-), while Cl2 in the side of the products has oxidation state 0. This shows that the oxidation state of chlorine increased, meaning that it is being oxidized.
