Nobelium
Nobelium, a radioactive, metallic chemical element. Nobelium does not occur in nature; it is produced artificially in trace amounts in cyclotrons and linear accelerators. The longest-lived isotope is nobelium 259, with a half-life of about 58 minutes.
Nobelium usually decays by emitting an alpha particle. It also decays by spontaneous fission—that is, the splitting of the nucleus into two or more parts. Nobelium has no commercial uses, but has been used in the study of nuclear fission.
Nobelium was discovered in 1958 by Albert Ghiorso, Glenn T. Seaborg, Torbjrn Sikkeland, and John R. Walton at the University of California, Berkeley. They prepared the element by bombarding isotopes of curium with carbon ions in a linear accelerator. A year earlier the discovery of nobelium had been reported by another group of scientists at the Nobel Institute for Physics at Stockholm. Although subsequent studies showed that this earlier claim was in error, the name nobelium proposed at that time was retained.
Symbol: No. Atomic number: 102. Atomic weight of most stable isotope: 259. Nobelium has 10 isotopes: No-250 to No-259. Nobelium is a transuranium element belonging to the actinide series of the Periodic Table and may have a valence of +2 or +3.