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Tm

Yb

Lu

Fm

Md

No

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Element Fact
Cesium is used in atomic clock. As in 1999, the best clock is accurate to a second in 20 million years.

Nobelium, No

nobelium sample

Atomic number: 102
Atomic mass: [259] (no stable nuclide)
Natural abundance: -
Isotopes: -

History and Production

Named after Alfred Nobel, discoverer of dynamite. It was discovered by A. Ghiorso, T. Sikkeland, J.R. Walton and G.T. Seaborg in 1958, from bombardment of a target of curium (95% 244Cm and 4.5% 246Cm) with 12C ions. The experiment was conducted in a heavy-ion linear accelerator and 254No (half-life=55 seconds) was produced. In fact, the first report of the element 102 was in 1957 by scientists working at the Nobel Institute for Physics in Stockholm, from bombardment of 244Cm with 13C ions. They claimed that an isotope with a half-life of 10 minutes has been produced. Subsequently, the name nobelium was assigned to the element. However, their results could not be repeated elsewhere. In 1966 confirmatory experiments carried out at Berkeley dismissed the possibility of element-102 having a half-life of 10 minutes. Of twelve isotopes now being discovered, the 255No isotope has the longest half-life of 3.1 minutes.

Physical Data

The properties of the element is not well known since only atomic quantities have been produced so far.

Interatomic distance: -
Melting point: n/a
Boiling point: n/a
Thermal conductivity/Wm-1K-1: 10 est. (27C)
Density/kgm-3: n/a

Standard Thermodynamic Data (atomic gas)

Enthalpy of formation: -
Gibbs free energy of formation: -
Entropy: -
Heat capacity: -

Electronic data

Electronic configuration: Electronic configuration: [Rn] 5f14 7s2
Term symbol: 1S0
Electron affinity: -   Electronegativity (Pauline): -
Ionization energy (first, second, third): 641.628, -, - kJ/mol

Chemical properties


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