Well, this atom could oxidize, and a water atom could oxidize. Now, if this atom decides to oxidize, this is our oxidation reaction. Now, if water decides to oxidize, namely the oxygen decides to oxidize, then this is our oxidation reactions. How do we choose which one occurs? Well, the one that's more negative than one that's lower on the reduction HAP reaction table. That's the one that is more likely to undergo oxidation.