'nŭnhĕk`sēəm), artificially produced radioactive chemical element element, 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...... Click the link for more information. ; symbol Uuh; at. no. 116; mass number of most stable isotope isotope , 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.
..... Click the link for more information. 292; m.p., b.p., sp. gr., and valence unknown. Situated in Group 16 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 table
..... Click the link for more information. , it is expected to have properties similar to those of polonium polonium , radioactive chemical element; symbol Po; at. no. 84; mass no. of most stable isotope 209; m.p. 254°C;; b.p. 962°C;; sp. gr. about 9.4; valence +2 or +4. Polonium is an extremely rare element found in uranium ores (about 0.1 gram per ton).
..... Click the link for more information. and tellurium tellurium [Lat.,=earth], semimetallic chemical element; symbol Te; at. no. 52; at. wt. 127.60; m.p. 450°C;; b.p. 990°C;; sp. gr. 6.24 at 20°C;; valence −2, +4, or +6. Tellurium is a lustrous, brittle, crystalline, silver-white metalloid.
..... Click the link for more information. .
In 1999 a research team at the Lawrence Berkeley National Laboratory in Calif. bombarded lead-208 atoms with high-energy krypton-86 ions to create, apparently, ununoctium ununoctium , artificially produced radioactive chemical element; symbol Uuo; at. no. 118. Scientists from the Joint Institute for Nuclear Research in Dubna, Russia, and Lawrence Livermore National Laboratory in California collaborated in the discovery of ununoctium
..... Click the link for more information. (element 118) atoms. The Uuo-293 isotope that they synthesized emitted an alpha particle to decay into Uuh-289, which has a life-life of about 0.6 millisecond, which then emitted an alpha particle to decay into ununquadium (element 114). Although the Berkeley laboratory retracted its claim for creating ununoctium in 2001, other research teams have since created ununhexium directly. No name has yet been adopted for element 116, which is therefore called ununhexium, from the Latin roots un for one and hex for six, under a convention for neutral temporary names proposed by the International Union of Pure and Applied Chemistry (IUPAC) in 1980.
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. ; transactinide elements transactinide 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.
..... Click the link for more information. ; 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 synthetic radioactive isotopes at the Univ.
..... Click the link for more information. .
Want to thank TFD for its existence? Tell a friend about us, add a link to this page, add the site to iGoogle, or visit the webmaster's page for free fun content.
| ?Page tools | ||
|---|---|---|
|