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Fermium (Fm): Actinides

Fermium (Fm)

What is Fermium?

Fermium (Fm), synthetic chemical element of the actinoid series of the periodic table, atomic number 100. Fermium (as the isotope fermium-255) is produced by the intense neutron irradiation of uranium-238 and was first positively identified by American chemist Albert Ghiorso and coworkers at Berkeley, California, in debris taken from the first thermonuclear (hydrogen bomb) test explosion (November 1952), “Mike,” in the South Pacific. The element was named after the Italian-born American physicist Enrico Fermi. All fermium isotopes are radioactive. Continue reading from Encyclopedia Britannica

The History

Fermium was discovered in 1953 in the debris of the first thermonuclear explosion which took place on a Pacific atoll on 1 November 1952. In this a uranium-238 bomb was used to provide the heat necessary to trigger a thermonuclear explosion. The uranium-238 had been exposed to such a flux of neutrons that some of its atoms had captured several of them, thereby forming elements of atomic numbers 93 to 100, and among the last of these was an isotope of element 100, fermium-255. News of its discovery was kept secret until 1955.

Meanwhile a group at the Nobel Institute in Stockholm had independently made a few atoms of fermium by bombarding uranium-238 with oxygen nuclei and obtained fermium-250, which has a half-life of 30 minutes. Continue reading from Royal Society of Chemistry

Fermium Facts

As the heaviest synthetic element that can be formed by neutron bombardment of lighter elements, fermium is the heaviest element that can be prepared in macroscopic quantities. There are 21 known isotopes of fermium, which range in atomic weights from 242 to 260. Fermium is artificially produced, though it did occur naturally once, with einsteinium, at the natural nuclear fission reactor at Oklo, Gabon. The element no longer exists at that site, however. Since fermium is found only in small quantities and all its isotopes have short half-lives, there is no commercial use for the element. Continue reading from Live Science

Chart of Elemental Properties for Fermium

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