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In nuclear physics, the valley of stability (also called the belt of stability, nuclear valley, energy valley, or beta stability valley) is a characterization of the stability of nuclides to radioactivity based on their binding energy. [1] Nuclides are composed of protons and neutrons.
In nuclear physics, the island of stability is a predicted set of isotopes of superheavy elements that may have considerably longer half-lives than known isotopes of these elements. It is predicted to appear as an "island" in the chart of nuclides , separated from known stable and long-lived primordial radionuclides .
All "stable" isotopes (stable by observation, not theory) are the ground states of nuclei, except for tantalum-180m, which is a nuclear isomer or excited state. The ground state, tantalum-180, is radioactive with half-life 8 hours; in contrast, the decay of the nuclear isomer is extremely strongly forbidden by spin-parity selection rules.
Of these, three elements (bismuth, thorium, and uranium) are primordial because they have half-lives long enough to still be found on the Earth, [d] while all the others are produced either by radioactive decay or are synthesized in laboratories and nuclear reactors. Only 13 of the 38 known-but-unstable elements have isotopes with a half-life ...
Nuclear stability is limited to those combinations of protons and neutrons described by the chart of the nuclides, also called the valley of stability.The boundaries of this valley are the neutron drip line on the neutron-rich side, and the proton drip line on the proton-rich side. [2]
A graph of isotope stability, with some of the magic numbers. In nuclear physics, a magic number is a number of nucleons (either protons or neutrons, separately) such that they are arranged into complete shells within the atomic nucleus. As a result, atomic nuclei with a "magic" number of protons or neutrons are much more stable than other nuclei.
The shaded region is the continent of stability. [1] The boundary to the continent of stability is determined by the situations where the Coulomb energy due to electric charge overcomes the binding energy, or where decay into atomic nuclei results in lower energy. The lowest energy mass number is proportional to the cube of the charge (atomic ...
Islands of stability are predicted to center near 294 Ds and 354 126, beyond which the model appears to deviate from several rules of the semi-empirical mass formula. [ 8 ] The general patterns of beta-stability are expected to continue into the region of superheavy elements , though the exact location of the center of the valley of stability ...