flerovium


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flerovium,

artificially produced radioactive chemical elementelement,
in chemistry, a substance that cannot be decomposed into simpler substances by chemical means. A substance such as a compound can be decomposed into its constituent elements by means of a chemical reaction, but no further simplification can be achieved.
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; symbol Fl; at. no. 114; mass number of most stable isotopeisotope
, in chemistry and physics, one of two or more atoms having the same atomic number but differing in atomic weight and mass number. The concept of isotope was introduced by F.
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 289; m.p., b.p., sp. gr., and valence unknown. Situated in Group 14 of the periodic tableperiodic 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 table entitled
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, it is expected to have properties similar to those of leadlead,
metallic chemical element; symbol Pb [Lat. plumbum]; at. no. 82; at. wt. 207.2; m.p. 327.502°C;; b.p. about 1,740°C;; sp. gr. 11.35 at 20°C;; valence +2 or +4.
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 and tintin,
metallic chemical element; symbol Sn [Lat. stannum]; at. no. 50; at. wt. 118.710; m.p. 231.9681°C;; b.p. 2,270°C;; sp. gr. 5.75 (gray), 7.3 (white); valence +2 or +4. Tin exhibits allotropy; above 13.
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.

Late in Dec., 1998, using plutonium-244 and calcium-48 isotopes provided by the Lawrence Livermore National Laboratory in Calif., Russian scientists employed a cyclotron at the Joint Institute for Nuclear Research in Dubna to produce an atom of element 114 with a mass number of 289. After a surprisingly long existence of 30 sec, the flerovium atom broke down successively into coperniciumcopernicium,
artificially produced radioactive chemical element; symbol Cn; at. no. 112; mass number of most stable isotope 285; m.p., b.p., sp. gr., and valence unknown.
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 (element 112), darmstadtiumdarmstadtium,
artificially produced radioactive chemical element; symbol Ds; at. no. 110; mass number of most stable isotope 281; m.p., b.p., sp. gr., and valence unknown. Situated in Group 10 of the periodic table, it is expected to have properties similar to those of platinum.
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 (element 110), and hassiumhassium
, artificially produced radioactive chemical element; symbol Hs; at. no. 108; mass number of most stable isotope 277; m.p., b.p., sp. gr., and valence unknown. Situated in Group 8 of the periodic table, it is expected to have properties similar to those of osmium.
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 (element 108). The Dubna team created a second isotope of flerovium, Fl-287, with a half-life measured in milliseconds, three months later. In 2011 the International Union of Pure and Applied Chemistry (IUPAC) confirmed the element's synthesis, but the confirmation was based on 2004 Dubna-Livermore work involving collisions of plutonium-242 and calcium-48, which produced Fl-287. The most stable isotope that has been confirmed is flerovium-289 with a half-life of approximately 2.6 sec. The name flerovium, after the Flerov Laboratory of Nuclear Reactions in Dubna, was proposed for the element in 2011 and was adopted by the International Union of Pure and Applied Chemistry (IUPAC) in 2012.

Flerovium is the first element of what might be an "island of stability" among heavy nuclei. Synthetic elements heavier than uranium are generally unstable. Scientists have for some time thought that elements number 114 and above might possess a very stable configuration of neutrons and protons because the nucleus would have a full complement of protons and neutrons making for longer life. The Dubna and Berkeley results seem to be evidence for this, since each isotope having an increasing number of neutrons (toward the optimum 184) has a longer half-life.

See also synthetic elementssynthetic 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.
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; transactinide elementstransactinide elements
, in chemistry, elements with atomic numbers greater than that of lawrencium (at. no. 103), the last member of the actinide series. See transuranium elements.
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; transuranium elementstransuranium 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.
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