^Binding energy per nucleon
1. is low for both heavy & light nuclei.
2. increases rapidly up to A = 20 & have peaks for 2He4, 6C12 & 8 O16 .
3. increases gradually after A = 20.
4. becomes less or more flat between A = 40 to 120.
Also it has average value in this region is 8.5 MeV.
5. has maximum value 8.8 MeV for the 26Fe56.
6. decrease after A =120 & drops to 7.6Mev for 92U238.
In order to increases the values of binding energies light nuclei undergo fusion while heavy nuclei undergo fission reactions i.e. heavy nuclei become more stable after fission & light nuclei become more stable after fusion.