Physics

The nuclear force is saturated: each nucleon can only bind to a limited number of neighbors before "running out of bonding capacity," much like how each person at a dinner table can only shake hands with those nearby. This means adding more nucleons doesn't proportionally increase total binding energy—you're just adding more nucleons to share the same amount of binding per particle. The result is that binding energy per nucleon plateaus around 8.8 MeV for nuclei with $A > 20$, making it nearly independent of nucleus size despite the dramatic growth in total binding energy.

The nuclear force is saturated: each nucleon can only bind to a limited number of neighbors before "running out of bonding capacity," much like how each person at a dinner table can only shake hands with those nearby. This means adding more nucleons doesn't proportionally increase total binding energy—you're just adding more nucleons to share the same amount of binding per particle. The result is that binding energy per nucleon plateaus around 8.8 MeV for nuclei with $A > 20$, making it nearly independent of nucleus size despite the dramatic growth in total binding energy.