lawrencium definition of lawrencium in the Free Online Encyclopedia.

lawrencium, artificially produced radioactive chemical element; symbol Lr; at. no. 103; mass number of most stable isotope 262; m.p. about 1,627°C;; b.p. and sp. gr. unknown; valence +3. Lawrencium is the last member of 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. of elements found in Group 3 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. . Lawrencium was the 11th 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. to be discovered. It was first prepared in 1961 (after three years of preliminary work) by Albert Ghiorso, Torbjørn Sikkeland, Almon E. Larsh, and Robert M. Latimer at the Univ. of California at Berkeley; a sample of californium isotopes was bombarded with a beam of boron nuclei from the heavy-ion linear accelerator. The resulting isotope, lawrencium-258, had 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 4.2 sec. The element was named for Ernest O. Lawrence Lawrence, Ernest Orlando, 1901–58, American physicist, b. Canton, S. Dak., grad. Univ. of South Dakota, 1922, Ph.D. Yale, 1925. Affiliated with the Univ.
..... Click the link for more information. , the inventor of the cyclotron. The symbol Lw was used at first, but it was changed to Lr in 1963. Ten isotopes, all of which are radioactive, are known; the most stable, lawrencium-262, has a half-life of 3.6 hours.

lawrencium

a transuranic element artificially produced from californium. Symbol: Lr; atomic no.: 103; half-life of most stable isotope, ²⁵⁶Lr: 35 seconds; valency: 3

lawrencium [′lȯ′ren·sē·əm]

(chemistry)

A chemical element, symbol Lr, atomic number 103; isotopes with mass numbers 251-263 have been discovered, all unilable; mass number 262 has the longest half-life (3.6 hours).

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lawrencium