Beyond iron, the binding energy per nucleon gradually decreases. This happens because the repulsive electrostatic force between protons begins to overcome the short-range strong nuclear force. Saturation Region: Between mass numbers , the binding energy is relatively constant (around
The shape of the curve dictates how we can extract energy from the atom:
. Nuclei in this "iron peak" (notably and Nickel-62 ) are the most tightly bound and stable in the universe. The curve of binding energy
The curve of binding energy is a graph that plots against the atomic mass number (
For very light elements like Hydrogen, the binding energy is low but increases sharply as mass number increases. This steep gradient explains why nuclear fusion (combining light nuclei) releases a massive amount of energy. Beyond iron, the binding energy per nucleon gradually
Heavy, less stable nuclei like Uranium-235 split into smaller fragments. These fragments are closer to the iron peak, meaning they have higher binding energy and release the "missing" energy during the split. Stellar Nucleosynthesis
Light nuclei move "up" the curve to become more stable by fusing together. This process powers stars like our Sun. Nuclei in this "iron peak" (notably and Nickel-62
) . It illustrates the stability of atomic nuclei and explains why certain nuclear reactions—like fusion and fission—release energy. Peak Stability: The curve peaks around a mass number of to