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Americium

Author: Robert Husted, Mollie Boorman

Atomic Number 95
Atomic Symbol Am
CAS ID No. 7440-35-9
Atomic Weight 0.0000 amu
Electron Configuration [Rn] 5f7 7s2
Melting Point 995.0 C
Boiling Point 2607 C
Density 13.600 g/cm3

History

(the Americas) Americium was the fourth transuranic element to be discovered; the isotope 241Am was identified by Seaborg, James, Morgan, and Ghiorso late in 1944 at the wartime metallurgical laboratory at the University of Chicago as the result of successive neutron capture reactions by plutonium isotopes in a nuclear reactor. 


Properties

The luster of freshly prepared americium metal is white and more silvery than plutonium or neptunium prepared in the same manner. It appears to be more malleable than uranium or neptunium and tarnishes slowly in dry air at room temperature. Americium must be handled with great care to avoid personal contamination. The alpha activity from 241Am is about three times that of radium. When gram quantities of 241Am are handled, the intense gamma activity makes exposure a serious problem. 241Am has been used as a portable source for gamma radiography. It has also been used as a radioactive glass thickness gauge for the flat glass industry and as a source of ionization for smoke detectors.




Last Update: 2011-02-16