Mendelevium
Mendelevium
is a
chemical
element in the
periodic
table with the symbol Md and the
atomic
number 101. Mendelevium is one of the synthetic
transuranic
chemical elements. It is the ninth transuranium element of the actinide series
History
It was named after the Russian chemist
Dmitri Mendeleev,
who devised the periodic table. It was first identified by
Albert
Ghiorso, Harvey, Greg Choppin, Thompson, and
Glenn
T. Seaborg in early in 1955 during the bombardment of the isotope 253Es with
helium ions in the
Berkeley
Radiation Laboratory 60-inch
cyclotron.
The isotope produced was 256Md, which has a half-life of 76 min. This first identification
was notable in that 256Md was synthesized on a one-atom-at-a-time basis.
Isotopes
Fourteen
isotopes are now recognized.
258Md has a half-life of 2 months. This isotope has been produced by the bombardment
of an isotope of
einsteinium
with ions of
helium. Eventually
enough 258Md should be made to determine its physical properties.
Uses
256Md
has been used to elucidate some of the chemical properties of mendelevium in
aqueous
solution.
Properties
Experiments seem to
show that the element possesses a moderately stable dipositive (II) oxidation
state in addition to the tripositive (III) oxidation state, which is characteristic
of the actinide elements.
References
