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The valley of stability can be helpful in interpreting and understanding properties of nuclear decay processes such as decay chains and nuclear fission. The uranium-238 series is a series of α (N and Z less 2) and β− decays (N less 1, Z plus 1) to nuclides that are successively deeper into the valley of stability.
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.
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 ...
An even number of protons or neutrons is more stable (higher binding energy) because of pairing effects, so even–even nuclides are much more stable than odd–odd. One effect is that there are few stable odd–odd nuclides: in fact only five are stable, with another four having half-lives longer than a billion years.
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.
For example, the extreme stability of helium-4 due to a double pairing of two protons and two neutrons prevents any nuclides containing five or eight nucleons from existing for long enough to serve as platforms for the buildup of heavier elements via nuclear fusion in Big Bang nucleosynthesis; only in stars is there enough time for this (see ...
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 ...