Binding Energy Graph

The binding energy is the energy required to separate a nucleus into its constituent nucleons. The binding energy per nucleon gives us the energy required to remove one proton or neutron from the nucleus.

The graph of binding energy per nucleon against nucleon number looks like this.

There is an increase in the energy required to remove one nucleon up until the peak of 8.8 MeV at Iron 56. The line then gently decreases. This means Iron is the most stable nucleus because it requires the largest amount of energy to remove one nucleon. This will also mean that there is the greatest mass defect.