PhysLink.com Logo

No - Nobelium

Nobelium

 Nobelium 
No
Atomic Number: 102
Atomic Weight: -259.0
Element Type: Rare Earth Metal
Crystal Structure:
Melting Point: 827.0°C = 1520.6°F = 1100.15 K
Boiling Point: °C = °F = K
Critical Temp: °C = °F = K
Atomic Radius: Å (Å = Angstrom = 10-10 m)
Covalent Radius: Å
Electronegativity:

History

(Alfred Nobel, discoverer of dynamite) Nobelium was unambiguiously discovered andidentified 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 toproduce 102No according to the 246Cm(12C, 4n) reaction.

In 1957 workers in the United States, Britain, and Sweden announced the discovery of anisotope of element 102 with a 10-minute half-life at 8.5 MeV, as a result of bombarding244Cm with 13C nuclei. On the basis of this experiment, the name nobelium wasassigned and accepted by the Commission on Atomic Weights of the International Union ofPure and Applied Chemistry.

The acceptance of the name was premature because both Russian and American efforts nowcompletely rule out the possibility of any isotope of Element 102 having a half-life of 10min in the vicinity of 8.5 MeV. Early work in 1957 on the search for this element, inRussia at the Kurchatov Institute, was marred by the assignment of 8.9 +/- 0.4 MeV alpharadiation with a half-life of 2 to 40 sec, which was too indefinite to support discoveryclaims.

Confirmatory experiments at Berkeley in 1966 have shown the existence of 254-102 with a55-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), theBerkeley group in 1967, suggested that the hastily given name nobelium along withthe symbol No , be retained.


Sources






Science Quote

'The strength and weakness of physicists is that we believe in what we can measure. And if we can't measure it, then we say it probably doesn't exist. And that closes us off to an enormous amount of phenomena that we may not be able to measure because they only happened once. For example, the Big Bang. ... That's one reason why they scoffed at higher dimensions for so many years. Now we realize that there's no alternative... '

Michio Kaku
(1947-)





All rights reserved. © Copyright '1995-'2018 PhysLink.com   Privacy Statement | Cookie Policy