The greater the reduction potential, the slower the element will oxidize.

Oxidation and reduction potential is a number given to an agent to quantify its ability to oxidize and reduce.

If the reduction potential of the cathode is greater than that of the anode, there will be a negative total reduction potential (reaction will not proceed spontaneously).

How likely chemical species are to gain electrons and therefore, be "reduced". Reduction potential is measured in volts(V) and the more positive the reduction potential value, the more likely it will be reduced.

Oxygen