What is "island of stability"

n. (context physics English) A grouping of isotopes of some transuranic elements that are predicted to be more stable that others due to having filled shells of protons and neutrons

In nuclear physics, the island of stability is the prediction that a set of heavy isotopes with a near magic number of protons and neutrons will temporarily reverse the trend of decreasing stability in elements heavier than uranium. Although predictions of the exact location differ somewhat, Klaus Blaum expects the island of stability to occur in the region near the isotope Ubn. Estimates about the amount of stability on the island are usually around a half-life of minutes or days, with some optimistic predictions expecting half-lives of millions of years.

Although the theory has existed since the 1960s, the existence of such superheavy, relatively stable isotopes has not been demonstrated. Like the rest of the superheavy elements, the isotopes on the island of stability have never been found in nature, and so must be created in an artificial nuclear reaction to be studied. However, scientists have not found a way to carry out such a reaction.

With an isotope graph of protons and neutrons with the third dimension of height being the binding energy, the stability region can actually be visualized as a valley (instead of an island).

Island of Stability was the phrase that Jimmy Carter used to description the circumstances of Iran under the leadership of the last Shah of Iran, Muhammad Reza Pahlavi.