Binding Energy

Image Source: web.mit.edu
  1. Energy required to remove a particular electron from an atom to an infinite distance.
  2. Amount of energy released at the creation of a particular isotope. Protons and neutron are held together by the “strong force”. The strong force only acts over very small distances but is able to overcome the electrostatic repulsion between protons. The magnitude of the bonding is measured by the binding energy per nucleon where “nucleon” is a collective name for neutrons and protons (sometimes called the “mass defect per nucleon”). The mass defect reflects the fact that the total mass of the nucleus is less than the sum of the mass of the individual neutrons and protons that formed it. The difference in mass is equivalent to the energy released in forming the nucleus. The general decrease in binding energy beyond iron is caused by the fact that, as the nucleus gets bigger, the ability of the strong force to counteract the electrostatic force between the protons becomes weaker. The most tightly bound isotopes are 62Ni, 58Fe, and 56Fe, which have binding energies of 8.8 MeV per nucleon. Elements heavier than these isotopes can yield energy by nuclear fission; lighter isotopes can yield energy by fusion.

Some or all content above used with permission from J. H. Wittke.