Consider the following proposed mechanism for a gas-phase reaction:
Step 1 NO₂(g) + F₂(g) → NO₂F(g) + F(g)
Step 2 F(g) + NO₂(g) → NO₂F(g)
Explain, in one or two sentences, why the fluorine atom F(g) is classified as an intermediate rather than a catalyst in this mechanism.