Work out nuclear binding energy instantly with clear inputs, formula shown and shareable results.
A nucleus weighs less than its separated parts, and that missing mass is the binding energy by E = mc^2. Adding hydrogen atom masses for the protons and neutron masses for the neutrons, then subtracting the measured atomic mass, gives the defect in atomic mass units; one u is 931.494 MeV. Iron-56 comes out near 492 MeV total, about 8.79 MeV per nucleon - the peak of nuclear stability.
Mass defect
defect = Z x m(H) + N x m(n) - measured atomic mass
Binding energy
BE = defect x 931.494 MeV/u
Because the measured atomic mass includes the electrons. Using hydrogen atoms cancels them out on both sides.
It sits at the maximum binding energy per nucleon, so fusion releases energy below it and fission releases energy above it. Stars cannot gain energy past iron.