History

Nobelium (named forAlfred Nobel, discoverer of dynamite).  In 1957 physicists at the Nobel Institute of Physics in Stockhlom, Sweden, announced that they had synthesized an isotope of element 102.  The team reported that they created an isotope with a half-life of 10 minutes at 8.5 MeV after bombarding ²⁴⁴Cm with ¹³C nuclei.  Based on this report, the Commission on Atomic Weights of the International Union of Pure and Applied Chemistry (IUPAC) assigned and accepted the name nobelium and the symbol No for the "new" element.  Subsequent Russian and American efforts to repeat the experiment failed.

The acceptance of the name was premature, for both Russian and American efforts now completely rule out the possibility of any isotope of nobelium having a half-life of 10 min in the vicinity of 8.5 MeV.  Early work in 1957 on the search for this element, in Russia at the Kurchatov Institute, was marred by the assignment of 8.9 +/- 0.4 MeV alpha radiation with a half-life of 2 to 40 sec, which was too indefinite to support claim to discovery.

In 1958, another group of scientists, Albert Ghiorso, Glenn T. Seaborg, Torbørn Sikkeland and John R. Walton, working at the Lawrence Radiation Laboratory in Berkeley, California, attempted to confirm the Nobel Institute's discovery. They were unable to produce any isotope of nobelium with a half-life of 10 minutes.  They were able to produce nobelium-254, with a half-life of three seconds, by bombarding curium-246 with carbon-12, using a new double-recoil technique.  A  new heavy-ion linear accelerator (HILAC) was used to bombard a thin target of curium (95% ²⁴⁴Cm and 4.5% ²⁴⁶Cm) with ¹²C ions to produce ¹⁰²No according to the ²⁴⁶Cm (¹²C, 4n) reaction.

A third group, working at the Joint Institute for Nuclear Reserch in Dubna, Russia, also could not duplicate the Nobel Institute's work but were able to confirm the Berkeley group's work. Credit for discovering nobelium was eventually given to the scientists working at Lawrence Radiation Laboratory, who decided to keep the name nobelium.   Today, the Lawrence Radiation Laboratory is known as the Lawrence Berkeley Laboratory.

In 1966 researchers at the University of California, Berkeley, confirmed the 1958 experiments and went on to show the existence of ²⁵⁴No (half-life 55 s), ²⁵²No (half-life 2.3 s), and ²⁵⁷No (half-life 23 s).  In view of the discover's traditional right to name an element, the Berkeley group, in 1967, suggested that the hastily given name nobelium, along with the symbol No, be retained.

Nobelium's most stable isotope, nobelium-259, has a half-life of about 58 minutes. It decays into fermium-255 through alpha decay or into mendelevium-259 through electron capture.

Since only tiny amounts of nobelium have ever been produced, there are currently no uses for it outside of basic scientific research.

Nobelium was the most recent element "of which the news had come to Harvard" when Tom Lehrer wrote "The Elements Song " and was therefore the element with the highest atomic number to be included.

Characteristics

Little is known about nobelium and only small quantities of it have ever been produced.   It has no known uses whatsoever outside of the laboratory.  Its most stable isotope, ²⁵⁹No, has a half-life of 58 minutes and decays to ²⁵⁵Fm through alpha decay or to ²⁵⁹Md through electron capture.

Isotopes

17 radioisotopes of nobelium have been characterized, with the most stable being ²⁵⁹No with a half-life of 58 minutes, ²⁵⁵No with a half-life of 3.1 minutes, and ²⁵³No with a half-life of 1.7 minutes.  All of the remaining radioactive isotopes have half-lives that are less than 56 seconds, and all of these have half-lives that are less than 2.4 seconds.  This element also has 4 meta state, ^251mNo (t_½ 1.7 seconds), ^252mNo ⁽t_½ 26 days^{), 253m}No ⁽t_½ 31 µs^{), 254m}No (t_½ 0.28 seconds).

The known isotopes of nobelium range in atomic weight from 248.08660 amu (²⁴⁸No) to 264.11235 amu (²⁶⁴No).  The primary decay mode before the most stable isotope, ²⁵⁹No, is alpha emission, and the primary mode after is spontaneous fission.  The primary decay products before ²⁵⁹No are element 100 (fermium) isotopes, and the primary products after are energy and subatomic particles.