Nuclear Binding Energy
Nuclear Binding Energy
The nuclear binding energy is an energy required to break up a nucleus into its components protons and neutrons. In essence, it is a quantitative measure of the nuclear stability. The concept of nuclear binding energy is based on Einstein's equation-E = mc2
where E is the energy, m is the mass and c is the velocity of light and according to which the energy and mass are inter-convertible.
Nucleus contains mainly two particles – protons and neutrons- in addition to many other elementary particles. Thus, the mass of the nucleus is the masses of protons and neutrons, but the experiments have shown that the sum of the masses of protons and neutrons is always greater than experimentally determined nuclear mass.
This mass difference is called Mass Defect or binding energy of nucleus.
In order to bind protons and neutrons together, some energy is needed, which is taken out of the masses of protons and neutrons. Some of the masses of protons and neutrons converted into an energy and utilizes that energy to bind the protons and neutrons within the nucleus.
The stability of nuclei of different mass number and the same mass number can be explained on the basis of binding energy per nucleon. The nucleus with large binding energy per nucleon is more stable. When a graph is plotted between binding energy per nucleon and mass number of different nuclei, the given grapg is obtained. This curve is called nuclear binding energy curve.
Except 2He4, 6C12 and 8O16, all the elements lie on this curve. Binding energy per nucleon of heavy elements is small. So, these elements are radioactive. The heavy elements are disintegrated and after disintegration, stable nuclei are formed because these stable nuclei have larger binding energy per nucleon.
The maximum binding energy per nucleon is 8.7 MeV of iron. So, iron is found in nature in large abundant. Maximum stable nuclei have near about 8MeV
Nuclear Stability
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