Enter your nucleus's Atomic Number (Z), Mass Number (A), and optionally its Atomic Mass to calculate the Binding Energy per Nucleon (BE/A) — plus the Total Binding Energy, Mass Defect, Mass Defect in Energy, and Number of Neutrons (N) that hold (or explain) the whole picture together.
Binding Energy per Nucleon (BE/A)
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Total Binding Energy
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Mass Defect
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Mass Defect (Energy)
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Number of Neutrons (N)
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Nuclear binding energy is the energy required to completely disassemble a nucleus into its individual protons and neutrons. It represents how tightly the nucleons are held together by the strong nuclear force.
BE/A allows comparison of nuclear stability across different nuclei. Higher values typically indicate more stable nuclei, with iron-56 having one of the highest BE/A values at about 8.8 MeV/nucleon.
Mass defect is the difference between the expected mass of separated nucleons and the actual atomic mass. It's calculated as Δm = [Z × m_proton + N × m_neutron] - M_atom, where the 'missing' mass converts to binding energy.
Calculations using experimental atomic masses are very accurate. When atomic mass is not provided, the calculator uses semi-empirical mass formula estimates, which are reasonably accurate for most nuclei but less precise for very light or very heavy elements.
This is Einstein's mass-energy equivalence (E=mc²) expressed in nuclear physics units. One atomic mass unit (amu) of mass converts to 931.494 MeV of energy, allowing conversion between mass defect and binding energy.
Iron-56 and nickel-62 have the highest BE/A values (around 8.8 MeV/nucleon), making them among the most stable nuclei. This is why fusion reactions release energy for light nuclei and fission releases energy for heavy nuclei.
Generally, nuclei with higher binding energy per nucleon are more stable and less likely to undergo radioactive decay. The BE/A curve peaks around mass number 56, which explains why elements like iron are so abundant in the universe.