Island of stability
The island of stability is a predicted set of isotopes of superheavy elements that may have considerably longer half-lives than known isotopes. It is predicted to appear as an ‘island’ in the chart of nuclides, separated from known stable and long-lived primordial radionuclides. Its theoretical existence is attributed to stabilizing effects of predicted’magic numbers’ of protons and neutrons in the superheavy mass region.
About Island of stability in brief
The island of stability is a predicted set of isotopes of superheavy elements that may have considerably longer half-lives than known isotopes. It is predicted to appear as an ‘island’ in the chart of nuclides, separated from known stable and long-lived primordial radionuclides. Its theoretical existence is attributed to stabilizing effects of predicted’magic numbers’ of protons and neutrons in the superheavy mass region. Several predictions have been made regarding the exact location of the island, though it is generally thought to center near copernicium and flerovium isotopes in the vicinity of the predicted closed neutron shell at N = 184. Estimates of the stability of the elements on the island are usually around a half-life of minutes or days; some estimates predict half-Lives of millions of years. Like the rest of the super heavy elements, the nuclide on the Island of stability have never been found in nature; thus, they must be created artificially in a nuclear reaction to be studied. Scientists have not found a way to carry out such a reaction, for it is likely that new types of reactions will be needed to populate nuclei near the center of the Island. The last element in the periodic table that has a stable isotope is lead, with stability generally decreasing in heavier elements. The stability of a nucleus is determined by its binding energy, higher binding energy conferring greater stability. The binding energy per nucleon increases with atomic number to a broad plateau around A = 60, then declines.
If a nucleus can be split into two parts that have a lower total energy, it is unstable. The nucleus can hold together for a finite time because there is a potential barrier opposing the split, but this barrier can be crossed by quantum tunneling. In heavier nuclei, larger numbers of uncharged neutrons are needed to reduce repulsion and confer additional stability. As early as 1914, the possible existence of elements with superheavy atomic numbers was suggested by German physicist Richard Swinne. In 1939, an upper limit of potential element synthesis was estimated around 104. In the early 1960s, this upper limit was extended to 108, and it was estimated that elements around Z=108 were around a source of radiation in cosmic rays. The discoverers of plutonium considered naming it \”imium\”, thinking it was the last element with instability with respect to spontaneous fission in microseconds, thinking it would decultually limit the existence of heavier elements with atomic numbers. The discovery of uranium, the heaviest known element, then suggested that that element would be around Z 100 or 100. Although he did not make any definitive observations in 1931, he hypothesized in 1931 that transuranium elements around Z=100 or100 were around that element. This prediction was later proved to be correct. As of 2019, 252 nuclided are observed to be stable ; generally, as the number of proons increases, stable nuclei have a higher neutron–proton ratio.
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This page is based on the article Island of stability published in Wikipedia (as of Nov. 22, 2020) and was automatically summarized using artificial intelligence.
