Nuclear binding energy is the energy required to split a nucleus of an atom into its components. The components are neutrons and protons. The binding energy of nuclei is always a positive number. Since all nuclei require net energy to separate them into constitutions, the mass of an atom’s nucleus is always less than the sum of the individual masses of the constituent protons and neutrons when separated. This difference is a measure of the nuclear binding energy. It is the result of force that holds the nucleus together. These forces result in the removal of energy when the nucleus is formed. The energy has mass and the mass is removed from the total mass of the original particles. The missing mass is a resulting nucleus. This missing mass is known as the mass defect.
An example of nuclear binding energy is carbon-12 nucleus. It contains 6 protons and 6 neutrons. The protons are positively charged and repel each other. The nuclear force overcomes the repulsion and causes them to stick together. The nuclear force is a close-range force virtually no effect of this force is observed outside the nucleus. The nuclear force also pulls neutrons together.
Calculating the nuclear binding energy of a nucleus is a few step calculations. First the mass defect must be determined. Once it is determined it must be converted into energy and expressed as energy per mole of atoms or as energy per nucleon.