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|Atomic Number:||102||Atomic Symbol:||No|
|Atomic Weight:||259||Electron Configuration:||2-8-18-32-32-8-2|
|Melting Point:||oC||Boiling Point:||oC|
|Description:||Man made radioactive metal.|
History(Alfred Nobel, discoverer of dynamite)
- Nobelium was unambiguiously discovered and identified in April 1958 at
Berkeley by A. Ghiorso, T. Sikkeland, J.R. Walton, and G.T. Seaborg, who used a
new double-recoil technique.
- A 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.
- In 1957 workers in the United States, Britain, and Sweden announced the
discovery of an isotope of element 102 with a 10-minute half-life at 8.5 MeV, as
a result of bombarding 244Cm with 13C nuclei.
- On the basis of this experiment, the name nobelium was assigned and
accepted by the Commission on Atomic Weights of the International Union of Pure
and Applied Chemistry.
- The acceptance of the name was premature because both Russian and American
efforts now completely rule out the possibility of any isotope of Element 102
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
- Confirmatory experiments at Berkeley in 1966 have shown the existence of
254-102 with a 55-s half-life, 252-102 with a 2.3-s half-life, and 257-102 with
a 23-s half-life.
- Following tradition giving the right to name an element to the
discoverer(s), the Berkeley group in 1967, suggested that the hastily given name
nobelium along with the symbol No , be retained.
IsotopesTen isotopes are now recognized, one of which -- 255-102 -- has
a half-life of 3 minutes.