Fermium

Fermium, symbol Fm, artificially created radioactive element with an atomic number of 100. Fermium is one of the transuranium elements in the actinide series of the periodic table (see Periodic Law). The element was isolated in 1952 from the debris of a hydrogen bomb explosion by the American chemist Albert Ghiorso and coworkers. Subsequently fermium was prepared synthetically in a nuclear reactor by bombarding plutonium with neutrons and in a cyclotron by bombarding uranium-238 with nitrogen ions. Isotopes with mass numbers from 242 to 260 have been produced; fermium-257, the longest-lived of these isotopes, has a half-life of about 100 days. The element was named fermium in 1955 in honor of the Italian-American nuclear physicist Enrico Fermi. Fermium does not have any industrial applications. See also Radioactivity.