If the reaction $$2 \mathrm{NO}_{2}(g)+\mathrm{F}_{2}(g) \longrightarrow 2 \mathrm{NO}_{2} \mathrm{~F}(g)$$ occurred by a one-step process, what would be the expected rate law for the reaction? The actual rate law is rate $=k\left[\mathrm{NO}_{2}\right]\left[\mathrm{F}_{2}\right]$, why is this a better rate law?