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|Atomic Number:||100||Atomic Symbol:||Fm|
|Atomic Weight:||257||Electron Configuration:||2-8-18-32-30-8-2|
|Melting Point:||oC||Boiling Point:||oC|
|Description:||Man made radioactive metal.|
- Fermium, the eighth discovered transuranium element of the actinide series,
was identified by Ghiorso and co-workers in 1952 in the debris from a
thermonuclear explosion in the pacific during work involving the University of
California Radiation Laboratory, Argonne National Laboratory, and Los Alamos
- The isotope produced was the 20-hour 255Fm.
- During 1953 and early 1954, while discovery of elements 99 and 100 was
withheld from publication for security reasons, a group from the Nobel Institute
of Physics in Stockholm bombarded 238U with 16O ions, and isolated a 30-min
alpha-emitter, which they ascribed to 250-100, without claiming discovery of the
- This isotope has since been identified positively, and the 30-min half-life
PropertiesThe chemical properties of fermium have been studied solely
with tracer amounts. In normal aqueous media, only the (III) oxidation state
appears to exist.
- 254Fm and heavier isotopes can be produced by intense neutron irradiation of
lower elements, such as plutonium, using a process of successive neutron capture
interspersed with beta decays until these mass numbers and atomic numbers are
- Sixteen isotopes of fermium are known to exist.
- 257Fm, with a half-life of about 100.5 days, is the longest lived.
- 250Fm, with a half-life of 30 minutes, has been shown to be a decay product
of element 254-102. Chemical identification of 250Fm confirmed the production of
element 102 (nobelium).