Introduction: 

Binding energy is the minimum energy by which either an electron is separated from an atom or protons and neutrons are separated from an atomic nucleus. So it is also termed separation energy. In physics, there are four important types of binding energy. They are nuclear binding energy, atomic binding energy, bond dissociation energy, and ionisation energy. A strong nuclear force binds charges together. As binding energy breaks the nuclear forces, it determines the strength of the bond between the nucleons. The energy required to disassemble nucleons is attained by bombarding the nucleus with high-energy particles. Nuclear fission and nuclear fusion involve such reactions.

History:

Nuclei consist of protons and neutrons. The mass of the nucleus is less than the individual masses of the protons and neutrons. The difference is used to calculate the nuclear binding energy that holds the nucleus together. This energy comes from electromagnetic interactions.

What is binding energy?

The concept of binding energy is applied by various scientists in atomic, nuclear, chemistry, and astrophysics. So binding energy definition is given as per the case studies on the different levels.

  • Nuclear binding energy is the energy by which the atomic nucleus breaks into constituent particles.
  • Binding energy in radioactivity is the energy by which the nucleus dissociates into single particles.
  • Binding energy in transition metals is the energy by which an atom is disassembled into free electrons and a nucleus.
  • The binding energy of an electron is the minimum energy by which an electron is removed from an atom.
  • The binding energy of satellites is the minimum energy needed to separate satellites from the gravitational pull of the planet.

Binding energy is calculated in terms of electron volts (eV).

Types:

There are many classifications in binding energy depending on various concepts. Here consider four major classifications. They are:

  • Nuclear binding energy: Nuclear binding energy determines the difference between the original mass and the expected mass depending on the sum of the masses of its non-bound constituents. This energy is comparable to the mass defect. So binding energy in terms of mass defect is given by:

E = m c2

where Δm is change in mass, c is the speed of light.

Nuclear binding energy also determines whether nuclear fusion or fission processes are appreciable or not.

  • Atomic binding energy: Binding energy in terms of atomic masses is given by:

BE = [Zmp+(A-Z)mn–zMA]c2

Where Z is the atomic number, A is the mass number, mp is mass of proton, mn is the mass of neutron, M is the mass of the nucleus  and c is the speed of light.

  • Bond dissociation energy: The energy that binds atoms together by a chemical bond is called bond dissociation energy. It is the energy required to split the molecule into atoms.
  • Ionisation energy: Ionisation energy is the energy by which the nucleus is separated into protons and neutrons. Helium has the highest ionisation energy.

Nuclear force:

The nuclear force is the strong force that is present in between two or more nucleons. It permits subatomic particles to bind together at short distances. Binding energy per nucleon gives the details of the nuclear force. With the increase in the number of nucleons, the net binding energy per nucleon increases. So, the greater the binding energy per nucleon, the more stable the nucleus is.

Nuclear fission and fusion:

Nuclear fission is a reaction in which an unstable nucleus splits into more stable nuclei with smaller masses. The difference in mass is considered as the mass defect or binding energy.

Nuclear fusion is a reaction in which unstable nuclei combine to form a stable nucleus. Here the total mass of the original nuclei is slightly greater than the mass of the nucleus formed. Here also, the mass defect is the binding energy that is released.

Factors affecting binding energy:

Binding energy depends on the following aspects:

  • Atomic number
  • Inversely proportional to the distance from the nucleus
  • Asymmetry between the number of protons and neutrons
  • Nuclear or Coulomb repulsive force between the protons

Conclusion:

The binding energy definition is given per the studies on the different levels. It includes atomic level, nuclear level, chemistry, and astrophysics. Binding energy is the minimum energy by which either an electron is separated from an atom or protons and neutrons are separated from an atomic nucleus. There are four major classifications in binding energy. They are nuclear binding energy, atomic binding energy, bond dissociation energy, and ionisation energy. Binding energy per nucleon gives the details of the nuclear force. Binding energy depends on atomic number, the asymmetry between the number of nucleons, Coulomb repulsive force, etc.