Eka-hafnium definition of Eka-hafnium in the Free Online Encyclopedia.

rutherfordium (rŭth'ərfôr`dēəm), artificially produced radioactive chemical element; symbol Rf; at. no. 104; mass number of most stable isotope 261; m.p., b.p., and sp. gr. unknown; valence +4. It is the first transuranium element 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. beyond the 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 considered a member of the series.
..... Click the link for more information. , thus being the first of the transactinide elements transactinide elements (trăns'ăk`tənīd'), in chemistry, elements with atomic numbers greater than that of lawrencium (at.
..... Click the link for more information. . Situated in Group 4 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 has properties similar to those of hafnium hafnium (hăf`nēəm), metallic chemical element; symbol Hf; at. no. 72; at. wt. 178.49; m.p. about 2,227°C;; b.p.
..... Click the link for more information. and zirconium zirconium (zərkō`nēəm), metallic chemical element; symbol Zr; at. no. 40; at. wt. 91.22; m.p. about 1,852°C;; b.p.
..... Click the link for more information. .

In 1964 a Soviet team led by G. N. Flerov at the Joint Institute for Nuclear Research at Dubna announced the discovery of element 104. They claimed to have isolated an isotope with mass number 260 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 0.3 sec by bombarding plutonium-242 atoms with neon-22 ions. Subsequently, they suggested that element 104 be named kurchatovium (symbol Ku) to honor Igor Kurchatov, a Soviet pioneer in nuclear physics. In 1969, an American research team led by A. Ghiorso at the Lawrence Berkeley National Laboratory announced that, while they had been unable to confirm the Dubna group's results, they had identified at least two isotopes of element 104 different from the one identified by the Soviet scientists. They bombarded californium-249 atoms with carbon-12 and carbon-13 ions to creates isotopes with mass numbers 257 (half-life of 4.8 sec), 259 (half-life of 3 sec), and possibly 258 (half-life of 13 msec). Disputing the Soviet claim of discovery, the Americans suggested the name rutherfordium to honor the British physicist Lord Ernest Rutherford Rutherford, Ernest Rutherford, 1st Baron, 1871–1937, British physicist, b. New Zealand. Rutherford left New Zealand in 1895, having earned three degrees from the Univ.
..... Click the link for more information. . An international committee set up to resolve such disputes decided in 1992 that the Berkeley and Dubna laboratories should share credit for the discovery. The syntheses of at least 10 isotopes of rutherfordium, with half-lives ranging from 0.5 msec (Rf-254) to 65 sec (Rf-261), have been confirmed.

In 1994 a committee of the International Union of Pure and Applied Chemistry (IUPAC), convened to resolve naming disputes for the transactinide elements, recommended that element 104 be named dubnium dubnium (d
..... Click the link for more information. in recognition of the work done at the Dubna laboratory. The committee also recommended that element 106, which had been called seaborgium seaborgium (sēbôr`gēəm), artificially produced radioactive chemical element; symbol Sg; at. no.
..... Click the link for more information. by the American team that discovered it, be called rutherfordium. In 1997, however, the name rutherfordium for element 104 was recognized internationally.

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. .

rutherfordium

a transactinide element produced by bombarding californium-249 nuclei with carbon-12 nuclei. Symbol: Rf; atomic number.: 104; atomic wt.: 261

rutherfordium [‚rəth·ər′fȯr·dē·əm]

(chemistry)

A chemical element, symbolized Rf, atomic number 104, a synthetic element; the first element beyond the actinide series, and the twelfth transuranium element.

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