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Columbia Encyclopedia entry: mendelevium

Mendeleviummĕndəlāv'ēəm, artificially produced radioactive chemical element; symbol Md; at. no. 101; mass no. of most stable isotope 258; m.p. 827°C; b.p. and sp. gr. unknown; valence +1, +2, +3. Mendelevium is a metal of the actinide series in Group 3 of the periodic table. The ninth transuranium element to be discovered, it is named for the Russian chemist Dmitri Ivanovich Mendeleev. The symbol Mv was used at first, but it was changed to Md in 1963. Sixteen isotopes of mendelevium are known. Mendelevium-256 (half-life about 76 min) was the first isotope produced; it was detected in 1955 by Albert Ghiorso, Bernard G. Harvey, Gregory R. Choppin, Stanley G. Thompson, and Glenn T. Seaborg, who produced it one atom at a time by bombarding einsteinium-253 with alpha particles in a cyclotron at the Univ. of California at Berkeley. This technique of producing and detecting single atoms has become the standard for the discovery of the elements beyond mendelevium in the periodic table. Little is known of the properties of this element, since its isotopes are unstable and difficult to produce. Mendelevium-258 (the most stable isotope) has a half-life of 52 days; its synthesis (by bombarding einsteinium-255 with alpha particles) may make possible studies of the physical and chemical properties of the element.

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Mendelevium is a synthetic element with the symbol Md and the atomic number 101. A metallic radioactive transuranic element of the actinides, mendelevium is synthesized by bombarding einsteinium with alpha particles and was named after Dimitri Ivanovich Mendeleev, who was responsible for the Periodic Table. Mendeleev’s periodic system was the key to discovery of elements for nearly a century. The name ‘Mendelevium’ was accepted by the International Union of Pure and Applied Chemistry. On the contrary, the symbol ‘Mv’ proposed by the discoverers wasn’t accepted and became ‘Md’ instead. Researchers have shown that mendelevium has a moderately stable...more »

Columbia Encyclopedia search results: mendelevium

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Periodic Table of the Elements: Mendelevium
Periodic Table of the Elements: MendeleviumAtomic Number:101Atomic Symbol:MdMendeleviumAtomic Weight:(258)ElectronConfiguration:2 · 8 · 1832 · 318 · 2
Md
Md, symbol for the element mendelevium.
Mv
Mv, former symbol of the element mendelevium, now Md.
einsteinium
Einsteinium [for Albert Einstein], artificially produced radioactive chemical element; symbol Es; at. no. 99; mass no. of most stable isotope 252; m.p. about 860°C; b.p. and sp. gr. unknown; v...
Seaborg, Glenn Theodore
Seaborg, Glenn Theodore, 1912–99, American chemist, b. Ishpeming, Mich., grad. Univ. of California at Los Angeles, 1934, Ph.D. Univ. of California at Berkeley, 1937. In 1939, he began teaching...
actinide series
Actinide series, a series of radioactive metallic elements in Group 3 of the periodic table. Members of the series are often called actinides, although actinium (at. no. 89) is not always cons...
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...
Elements (table)
ElementsElementSymbolAtomic NumberAtomic Weight1Melting Point(Degrees Celsius)Boiling Point(Degrees Celsius)1 Parentheses indicate most stable isotope.actiniumAc89227.02781050.3200....

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