Editing Transuranium element (section)

==Overview==
{{Periodic table (transuranium element)}}

Of the elements with atomic numbers 1 to 92, most can be found in nature, having stable [[isotope]]s (such as [[oxygen]]) or very long-lived [[radioisotope]]s (such as [[uranium]]), or existing as common [[decay product]]s of the decay of uranium and [[thorium]] (such as [[radon]]). The exceptions are [[technetium]], [[promethium]], [[astatine]], and [[francium]]; all four occur in nature, but only in very minor branches of the uranium and thorium decay chains, and thus all save francium were first discovered by synthesis in the laboratory rather than in nature.

All elements with higher atomic numbers have been first discovered in the laboratory, with [[neptunium]] and [[plutonium]] later discovered in nature. They are all [[radioactive]], with a [[half-life]] much shorter than the [[age of the Earth]], so any primordial (i.e. present at the Earth's formation) atoms of these elements, 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 [[nuclear weapon]]s. These two elements are generated by [[neutron capture]] in [[uranium ore]] with subsequent [[beta decay]]s (e.g. [[Uranium-238|{{sup|238}}U]] + [[Neutron|n]] → [[Uranium-239|{{sup|239}}U]] → [[Neptunium-239|{{sup|239}}Np]] → [[Plutonium-239|{{sup|239}}Pu]]).

All elements beyond plutonium are entirely [[synthetic element|synthetic]]; they are created in [[nuclear reactor]]s or [[particle accelerator]]s. The half-lives of these elements show a general trend of decreasing as atomic numbers increase. There are exceptions, however, including several isotopes of [[curium]] and [[dubnium]]. Some heavier elements in this series, around atomic numbers 110–114, are thought to break the trend and demonstrate increased nuclear stability, comprising the theoretical [[island of stability]].<ref>{{cite book |editor-first=Glenn |editor-last=Considine |title=Van Nostrand's Scientific Encyclopedia |edition=9th |location=New York |publisher=Wiley Interscience |year=2002 |page=738 |isbn=978-0-471-33230-5 }}</ref>

Transuranic elements are difficult and expensive to produce, and their prices increase rapidly with atomic number. As of 2008, the cost of weapons-grade plutonium was around $4,000/gram,<ref>{{cite web|url=https://hypertextbook.com/facts/2008/AndrewMorel.shtml|title=Price of Plutonium|last=Morel|first=Andrew|date=2008|editor-last=Elert|editor-first=Glenn|publisher=The Physics Factbook|archive-url=https://web.archive.org/web/20181020094114/https://hypertextbook.com/facts/2008/AndrewMorel.shtml|archive-date=20 October 2018|url-status=live}}</ref> and [[californium]] exceeded $60,000,000/gram.<ref>{{cite report|citeseerx=10.1.1.499.1273|title=Applications and Availability of Californium-252 Neutron Sources for Waste Characterization|last1=Martin|first1=Rodger C.|last2=Kos|first2=Steve E.|date=2001|url=https://archive.org/details/ApplicationsAndAvailabilityOfCalifornium252NeutronSourcesForWasteCharacterization}}</ref> [[Einsteinium]] is the heaviest element that has been produced in macroscopic quantities.<ref>{{cite book|title=The Chemistry of the Actinide and Transactinide Elements|last=Silva|first=Robert J.|publisher=[[Springer Science+Business Media]]|year=2006|isbn=978-1-4020-3555-5|editor1-last=Morss|editor-first=Lester R.|edition=Third|location=Dordrecht, The Netherlands|chapter=Fermium, Mendelevium, Nobelium and Lawrencium|ref=CITEREFHaire2006|editor2-last=Edelstein|editor2-first=Norman M.|editor3-last=Fuger|editor3-first=Jean}}</ref>

Transuranic elements that have not been discovered, or have been discovered but are not yet officially named, use [[International Union of Pure and Applied Chemistry|IUPAC]]'s [[systematic element name]]s. The naming of transuranic elements may be a source of [[List of chemical element naming controversies|controversy]].