On the basis of the following proposed mechanism, account for the experimental fact that the rate law for the decomposition 2N₂O₅ => 4NO₂(g) + O₂(g) is v = k[N₂O₅]²:
1. N₂O₅ => NO₂ + NO₃ (k1)
2. NO₂ + NO₃ => NO₂ + NO₂ (k2)
3. NO₂ + NO₃ => NO + NO₂ + O₂ (k3)
4. NO + NO₂ + O₂ => NO₂ + NO₂ + NO₂