unnilennium definition of unnilennium in the Free Online Encyclopedia.

meitnerium (mītnĭr`ēəm), artificially produced radioactive chemical element; symbol Mt; at. no. 109; mass number of most stable isotope 266; m.p., b.p., sp. gr., and valence unknown. Situated in Group 9 of the periodic table periodic table, chart of the elements arranged according to the periodic law discovered by Dmitri I. Mendeleev and revised by Henry G. J. Moseley . In the periodic table the elements are arranged in columns and rows according to increasing atomic number (see the
..... Click the link for more information. it is expected to have properties similar to those of iridium iridium (ĭrĭd`ēəm), metallic chemical element; symbol Ir; at. no. 77; at. wt. 192.22; m.p. about 2,410°C;; b.p.
..... Click the link for more information. .

In 1982 a German research team led by P. Armbruster and G. Münzenberg at the Institute for Heavy Ion Research at Darmstadt bombarded bismuth-209 atoms with iron-58 ions. On the tenth day of the experiment, one atom was unambiguously identified as an isotope of element 109 with mass number 266 and a half-life half-life, measure of the average lifetime of a radioactive substance (see radioactivity ) or an unstable subatomic particle. One half-life is the time required for one half of any given quantity of the substance to decay.
..... Click the link for more information. of 3.4 msec. The Germans suggested the name meitnerium to honor the Austrian-Swedish physicist and mathematician Lise Meitner Meitner, Lise (lē`zə mīt`nər), 1878–1968, Austrian-Swedish physicist and mathematician.
..... Click the link for more information. . This name was recognized internationally in 1997.

See also synthetic elements synthetic elements, in chemistry, radioactive elements that were not discovered occurring in nature but as artificially produced isotopes. They are technetium (at. no. 43), which was the first element to be synthesized, promethium (at. no. 61), astatine (at. no.
..... Click the link for more information. ; transuranium elements transuranium elements, in chemistry, radioactive elements with atomic numbers greater than that of uranium (at. no. 92). All the transuranium elements of the actinide series were discovered as synthetic radioactive isotopes at the Univ.
..... Click the link for more information. .

meitnerium

a synthetic element produced in small quantities by high-energy ion bombardment. Symbol: Mt; atomic no.: 109

meitnerium [mīt′nir·ē·əm]

(chemistry)

A chemical element, symbolized Mt, atomic number 109, a synthetic element; the seventeenth transuranium element.

meitnerium (redirected from unnilennium)

meitnerium
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