Transuranium element 31537 226081154 2008-07-16T19:12:51Z El C 92203 Reverted edits by [[Special:Contributions/137.113.103.122|137.113.103.122]] ([[User talk:137.113.103.122|talk]]) to last version by Nergaal {{Refimprove|date=May 2007}} In [[chemistry]], '''transuranium elements''' (also known as '''transuranic elements''') are the [[chemical element]]s with [[atomic number]]s greater than 92 (the atomic number of [[uranium]]). Of the elements with atomic numbers 1 to 92, all but four ([[technetium]], [[promethium]], [[astatine]], and [[francium]]) occur in easily detectable quantities on earth, having stable, or very long half life isotopes, or are created as common products of the decay of uranium. All of the elements with higher atomic numbers, however, have been first discovered artificially, and other than [[plutonium]] and [[neptunium]], none occur naturally on earth. They are all [[radioactive]], with a [[half-life]] much shorter than the [[age of the Earth]], so any atoms of these elements, if they ever were present at the earth's formation, have long since decayed. Trace amounts of neptunium and plutonium form in some uranium-rich rock, and small amounts are produced during atmospheric tests of [[atomic weapons]]. The Np and Pu generated are from [[neutron capture]] in uranium ore with two subsequent [[beta decay]]s ([[Uranium-238|<sup>238</sup>U]] → [[Uranium-239|<sup>239</sup>U]] → [[Neptunium-239|<sup>239</sup>Np]] → [[Plutonium-239|<sup>239</sup>Pu]]). Those that can be found on earth now are artificially generated [[synthetic element]]s, via [[nuclear reactor]]s or [[particle accelerator]]s. The half lives of these elements show a general trend of decreasing with atomic number. There are exceptions, however, including [[dubnium]] and several isotopes of [[curium]]. Further anomalous elements in this series have been predicted by [[Glenn T. Seaborg]], and are categorised as the “[[island of stability]].” Transuranic elements that have not been discovered, or have been discovered but are not yet officially named, use [[IUPAC]]'s [[systematic element name]]s. The naming of transuranic elements is a source of [[element naming controversy|controversy]]. [[Image:Periodic Table by Radioactivity.PNG|right|450px|thumb|Periodic table colored according to the radioactivity of the most stable isotope .<br> (1) <span style="color:blue">stable elements.</span><br> (2) <span style="color:green">radioactive elements with isotopes with very long decay half-times.</span> Their half-live of over a million years gives them very small, if not negligible radioactivities and thus may be handled without any precautions.</span><br> (3) <span style="color:#FFD800">radioactive elements that may present low health hazards.</span> Their half-time of over 500 years allows them to have commercial applications due to the fact that their radiation levels are near the [[background radiation|background one]].<br> (4) <span style="color:#FF7E00">radioactive elements that are known to pose high safety risks.</span> Their half-life of over a day and their radioactivity levels make them have little potential for any commercial use.<br> (5) <span style="color:red">highly radioactive elements.</span> Because of their half-time as low as a couple of minutes, they pose severe health risks and is unlikely that they will receive any use outside basic research.</span><br> (6) <span style="color:brown">extremely radioactive elements.</span> Very little is known about these elements, and will likely never receive any attention outside research laboratories.</span>]] == Discovery and naming of transuranium elements == The majority of the transuranium elements were produced by three groups: * A group at the [[University of California, Berkeley]], under three different leaders: ** [[Edwin Mattison McMillan]], first to produce a transuranium element: *** 93. [[neptunium]], Np, named after the planet [[Neptune (planet)|Neptune]], as it follows [[uranium]] and Neptune follows [[Uranus (planet)|Uranus]] in the [[Gas giants|planetary sequence]]. ** [[Glenn T. Seaborg]], next in order, who produced: *** 94. [[plutonium]], Pu, named after the dwarf planet [[Pluto (planet)|Pluto]], following the same naming rule as it follows neptunium and Pluto follows Neptune in the pre-2006 planetary sequence. *** 95. [[americium]], Am, named because it is an analog to [[europium]], and so was named after the continent where it was first produced. *** 96. [[curium]], Cm, named after [[Pierre Curie|Pierre]] and [[Maria Sklodowska-Curie|Marie Curie]], famous scientists who separated out the first [[radioactive]] elements. *** 97. [[berkelium]], Bk, named after the city of [[Berkeley, California|Berkeley]], where the University of California at Berkeley is located. *** 98. [[californium]], Cf, named after the state of [[California]], where the university is located. ** [[Albert Ghiorso]], who had been on Seaborg's team when they produced curium, berkelium, and californium, took over as director to produce: *** 99. [[einsteinium]], Es, named after the theoretical physicist [[Albert Einstein]]. *** 100. [[fermium]], Fm, named after [[Enrico Fermi]], the physicist who produced the first controlled [[chain reaction]]. *** 101. [[mendelevium]], Md, named after the [[Russia]]n chemist [[Dmitri Mendeleev]], credited for being the primary creator of the [[periodic table]] of the [[chemical element]]s. *** 102. [[nobelium]], No, named after [[Alfred Nobel]]. *** 103. [[lawrencium]], Lr, named after [[Ernest O. Lawrence]], a physicist best known for development of the [[cyclotron]], and the person for whom the [[Lawrence Livermore National Laboratory]] (which hosted the creation of these transuranium elements) was named. * A group at the '''[[Joint Institute for Nuclear Research]]''' in '''[[Dubna]]''', [[Russia]] (then the [[Soviet Union]]) who produced: ** 104. [[rutherfordium]], Rf, named after [[Ernest Rutherford]], who was responsible for the concept of the [[atomic nucleus]]. ** 105. [[dubnium]], Db, an element that is named after the city of Dubna, where the JINR is located, ** 106. [[seaborgium]], Sg, named after [[Glenn T. Seaborg]]. This name caused controversy because Seaborg was still alive, but eventually became accepted by international chemists. ** 107. [[bohrium]], Bh, named after the [[Denmark|Danish]] physicist [[Niels Bohr]], important in the elucidation of the structure of the [[atom]]. * A group at the [[Gesellschaft für Schwerionenforschung]] (Society for Heavy Ion Research) in [[Darmstadt, Hessen]], [[Germany]], under Peter Armbruster, who prepared: ** 108. [[hassium]], Hs, named after the [[Latin]] form of the name of [[Hessen]], the [[Germany|German]] ''[[States of Germany|Bundesland]]'' where this work was performed. ** 109. [[meitnerium]], Mt, named after [[Lise Meitner]], an Austrian physicist who was one of the earliest scientists to become involved in the study of [[nuclear fission]]. ** 110. [[darmstadtium]], Ds named after [[Darmstadt]], [[Germany]], the city in which this work was performed. ** 111. [[roentgenium]], Rg named after [[Wilhelm Conrad Röntgen]], discoverer of X-rays. == List of the transuranic elements == * 93 [[neptunium]] Np * 94 [[plutonium]] Pu * 95 [[americium]] Am * 96 [[curium]] Cm * 97 [[berkelium]] Bk * 98 [[californium]] Cf * 99 [[einsteinium]] Es * 100 [[fermium]] Fm * 101 [[mendelevium]] Md * 102 [[nobelium]] No * 103 [[lawrencium]] Lr * [[Transactinide element]]s ** 104 [[rutherfordium]] Rf ** 105 [[dubnium]] Db ** 106 [[seaborgium]] Sg ** 107 [[bohrium]] Bh ** 108 [[hassium]] Hs ** 109 [[meitnerium]] Mt ** 110 [[darmstadtium]] Ds ** 111 [[roentgenium]] Rg ** 112 [[ununbium]] Uub* ** 113 [[ununtrium]] Uut* ** 114 [[ununquadium]] Uuq* ** 115 [[ununpentium]] Uup* ** 116 [[ununhexium]] Uuh* ** 118 [[ununoctium]] Uuo* <nowiki>*</nowiki>The existence of these elements has been confirmed, however the names and symbols given are provisional as no names for the elements have been agreed on. == Super-heavy atoms == {{main|Superheavy element}} [[Image:Super heavy elements.svg|thumb|250px|right|Position of the super-heavy elements in the periodic table.]] '''Super-heavy atoms''', (''super heavy elements'', commonly abbreviated '''SHE'''), are the [[transactinide element]]s beginning with [[rutherfordium]] (atomic number 104). They have only been made artificially, and currently serve no useful purpose because their short half-lives cause them to decay after a few minutes to just a few milliseconds, which also makes them extremely hard to study. Super-heavy atoms have all been created during the latter half of the 20th century and are continually being created during the 21st century as technology advances. They are created through the bombardment of elements in a [[particle accelerator]], for example the [[nuclear fusion]] of [[californium]]-249 and [[carbon]]-12 creates [[rutherfordium]]. These elements are created in quantities on the atomic scale and no method of mass creation has been found. == See also == * [http://www.transfermium.net/ Super Heavy Elements network official website] (network of the European integrated infrastructure initiative EURONS) * [[Bose-Einstein condensate]] (also known as ''Superatom'') * [[Island of stability]] * [[Minor actinides]] * [http://www.phys.huji.ac.il/~marinov/index.htm Prof. [[Amnon Marinov]]'s Site with related publications) ==References== <references/> * http://alsos.wlu.edu/qsearch.aspx?browse=science/Transuranium+Elements Annotated bibliography for the transuranic elements from the Alsos Digital Library for Nuclear Issues. * http://web.fccj.org/~ethall/uranium/uranium.htm <!-- Please cite source's to help with the encyclopedia's general verifiability concerns. Tips for referencing: see: [[WP:CITET]]. 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