In nuclear physics, the valley of stability is a characterization of the stability of nuclides to radioactivity based on their binding energy. Nuclides are composed of protons and neutrons. The shape
The negative of binding energy per nucleon for the stable nuclides located along the bottom of the valley of stability. Iron-56 is about the most stable nuclide, and it is about the lowest point within the valley of stability.
The negative of binding energy per nucleon for nuclides with atomic mass number 125 plotted as a function of atomic number. The profile of binding energy across the valley of stability is roughly a parabola. Tellurium-125 (52Te) is stable, while antimony-125 (51Sb) is unstable to β− decay.
Fragment of table of nuclides as seen on a monument in front of University of Warsaw's Centre of New Technologies, with the four elements named by or for Polish scientists shown in the title ("including Po, Ra, Cm, Cn") and below the table: polonium (84Po) discovered in 1898, radium (88Ra) discovered in 1898, curium (96Cm) discovered in 1944, copernicium (112Cn) discovered in 1996.