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Columbia Encyclopedia entry: berkelium

Berkeliumbûr'klēəm [from Berkeley], artificially produced radioactive chemical element; symbol Bk; at. no. 97; mass no. of most stable isotope 247; m.p. about 1,050°C; b.p. about 2,590°C; sp. gr. 14 (estimated); valence +3, +4. Berkelium is believed to be similar to the other members of the actinide series and to terbium, its homolog in the lanthanide series. It is found in Group 3 of the periodic table. The 10 isotopes of berkelium that are known are all radioactive; the element has not been found in the earth's crust. Berkelium-247, the most stable isotope (half-life about 1,400 years), is difficult to produce; berkelium-249 (half-life 314 days) is more easily produced in weighable quantities and is used in studies of berkelium chemistry. Berkelium metal exists in two crystal modifications (see allotropy) and is chemically reactive; the chloride, fluoride, sulfide, nitrate, sulfate, perchlorate, oxide, and dioxide have been produced. Berkelium was the fifth transuranium element to be synthesized. It was discovered late in 1949 by Glenn T. Seaborg, Stanley G. Thompson, and Albert Ghiorso, who produced it by bombarding americium-241 with alpha particles in the cyclotron of the Univ. of California at Berkeley. Weighable quantities of the pure element were first isolated by Thompson and B. B. Cunningham in 1958.

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Berkelium is a synthetic element with the symbol Bk and atomic number 97. A radioactive metallic element in the actinide series, berkelium was first synthesized by bombarding americium with alpha particles and was named after the University of California, Berkeley. Berkelium was the fifth transuranic element to be synthesized. Weighable amounts of 249 Bk make it possible to determine some of its properties using macroscopic quantities. It is a silvery metal that would easily oxidize in air at elevated temperatures and would be soluble in dilute mineral acids. X-ray diffraction techniques have been used to identify various berkelium compounds...more »

Columbia Encyclopedia search results: berkelium

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Periodic Table of the Elements: Berkelium
Periodic Table of the Elements: BerkeliumAtomic Number:97Atomic Symbol:BkBerkeliumAtomic Weight:(247)ElectronConfiguration:2 · 8 · 1832 · 278 · 2
Bk
Bk, symbol for the element berkelium.
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...
californium
Californium [from California], artificially produced, radioactive metallic chemical element; symbol Cf; at. no. 98; mass no. of most stable isotope 251; m.p. about 900°C; b.p. about 1,470°C; d...
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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