Editing Synthetic element

{{short description|Chemical elements that do not occur naturally}}
[[File:Redgreen colorblind changed version of Synthetic Mod.png|thumb|441x441px|{{legend|#CC00FF|Synthetic elements}}{{legend|#A1FB8E|Rare radioactive natural elements; often produced artificially}}
{{Legend striped|#C9181F|#C9181F|Common radioactive natural elements}}]]
A '''synthetic element''' is a known [[chemical element]] that does not occur naturally on [[Earth]]: it has been created by human manipulation of [[fundamental particle]]s in a [[nuclear reactor]], a [[particle accelerator]], or the explosion of an [[atomic bomb]]; thus, it is called "synthetic", "artificial", or "man-made". The synthetic elements are those with atomic numbers 95–118, as shown in purple on the accompanying [[periodic table]]:<ref name=kulkarni>{{cite web |last1=Kulkarni |first1=Mayuri |title=A Complete List of Man-made Synthetic Elements |url=https://sciencestruck.com/synthetic-elements |website=ScienceStuck |date=15 June 2009 |access-date=15 May 2019}}</ref> these 24 elements were first created between 1944 and 2010. The mechanism for the creation of a synthetic element is to force additional protons into the [[Atomic nucleus|nucleus]] of an element with an [[atomic number]] lower than 95. All known (see: [[Island of stability]]) synthetic elements are unstable, but they [[radioactive decay|decay]] at widely varying rates; the [[half-lives]] of their longest-lived isotopes range from microseconds to millions of years. 

Five more elements that were first created artificially are strictly speaking not ''synthetic'' because they were later found in nature in trace quantities: [[Technetium|<sub>43</sub>Tc]], [[Promethium|<sub>61</sub>Pm]], [[Astatine|<sub>85</sub>At]], [[Neptunium|<sub>93</sub>Np]], and [[Plutonium|<sub>94</sub>Pu]]; though they are sometimes classified as synthetic alongside exclusively artificial elements.<ref>See periodic table [https://www.japantimes.co.jp/news/2016/06/09/national/science-health/name-nihonium-chosen-thank-japanese-public-support-physicist-says/ here] for example.</ref> The first, technetium, was created in 1937.<ref>{{cite web |title=WebElements Periodic Table » Technetium » historical information |url=https://www.webelements.com/technetium/history.html |website=www.webelements.com |publisher=Webelements |access-date=7 November 2019}}</ref> Plutonium (Pu, atomic number 94), first synthesized in 1940, is another such element. It is the element with the largest number of protons (atomic number) to occur in nature, but it does so in such tiny quantities that it is far more practical to synthesize it. Plutonium is known mainly for its use in atomic bombs and nuclear reactors.<ref>{{cite web |last1=Bradford |first1=Alina |title=Facts About Plutonium |url=https://www.livescience.com/39871-facts-about-plutonium.html |website=LiveScience |date=8 December 2016 |access-date=16 May 2019}}</ref>

No elements with atomic numbers greater than 99 have any uses outside of scientific research, since they have extremely short half-lives, and thus have never been produced in large quantities.

==Properties==
All elements with atomic number greater than 94 decay quickly enough into lighter elements such that any [[atom]]s of these that may have existed when the Earth formed (about 4.6&nbsp;billion years ago) have long since decayed.<ref>{{cite web |last1=Redd |first1=Nola |title=How Was Earth Formed? |url=https://www.space.com/19175-how-was-earth-formed.html |website=Space.com |date=November 2016 |access-date=16 May 2019}}</ref><ref>{{cite web |title=Synthetic elements |url=https://www.infoplease.com/encyclopedia/science/chemistry/elements/synthetic-elements |website=Infoplease |access-date=16 May 2019}}</ref> Synthetic elements now present on Earth are the product of atomic bombs or experiments that involve [[nuclear reactor]]s or [[particle accelerator]]s, via [[nuclear fusion]] or [[neutron absorption]].<ref>{{cite web |last1=Kulkarni |first1=Mayuri |title=A Complete List of Man-made Synthetic Elements |url=https://sciencestruck.com/synthetic-elements |website=ScienceStuck |date=15 June 2009 |access-date=16 May 2019}}</ref>

[[Atomic mass]] for natural elements is based on weighted average abundance of natural [[isotope]]s in [[Earth]]'s [[crust (geology)|crust]] and [[atmosphere]]. For synthetic elements, there is no "natural isotope abundance". Therefore, for synthetic elements the total [[nucleon]] count ([[proton]]s plus [[neutron]]s) of the most stable [[isotope]], i.e., the isotope with the longest [[half-life]]—is listed in brackets as the atomic mass.

==History==
===Technetium===
The first element to be synthesized, rather than discovered in nature, was [[technetium]] in 1937.<ref>{{cite web |last1=Helmenstine |first1=Anne Marie |title=Technetium or Masurium Facts |url=https://www.thoughtco.com/technetium-or-masurium-facts-606601 |publisher=ThoughtCo |access-date=15 May 2019}}</ref> This discovery filled a gap in the [[periodic table]], and the fact that technetium has no [[stable isotope]]s explains its natural absence on Earth (and the gap).<ref>{{cite web |title=Technetium decay and its cardiac application |url=https://www.khanacademy.org/test-prep/mcat/physical-sciences-practice/physical-sciences-practice-tut/e/cs-passage-4  |publisher=Khan Academy |access-date=15 May 2019}}</ref> With the longest-lived isotope of technetium, <sup>97</sup>Tc, having a [[1e14 s|4.21-million-year]] half-life,{{NUBASE2020|ref}} no technetium remains from the formation of the Earth.<ref>{{cite web |last1=Stewart |first1=Doug |title=Technetium Element Facts |url=https://www.chemicool.com/elements/technetium.html |website=Chemicool |access-date=15 May 2019}}</ref><ref>{{cite web |last1=Bentor |first1=Yinon |title=Periodic Table: Technetium |url=http://www.chemicalelements.com/elements/tc.html |website=Chemical Elements |access-date=15 May 2019}}</ref> Only minute traces of technetium occur naturally in Earth's crust—as a [[fission product|product]] of [[spontaneous fission]] of <sup>238</sup>U, or from [[neutron capture]] in [[molybdenum]]—but technetium is present naturally in [[red giant]] stars.<ref name=CRC>{{cite book |first = C. R. |last = Hammond |chapter = The Elements |title = Handbook of Chemistry and Physics |edition = 81st |publisher = CRC press |isbn = 978-0-8493-0485-9 |date = 2004 |url-access = registration |url = https://archive.org/details/crchandbookofche81lide }}</ref><ref>{{cite journal|doi = 10.1126/science.114.2951.59|pmid = 17782983|date = 1951|last1 = Moore|first1 = C. E.|title = Technetium in the Sun|volume = 114|issue = 2951|pages = 59–61|journal = Science |bibcode=1951Sci...114...59M}}</ref><ref>{{cite journal|doi = 10.1021/ac961159q|title = Analysis of Naturally Produced Technetium and Plutonium in Geologic Materials|date = 1997|last1 = Dixon|first1 = P.|journal = Analytical Chemistry|volume = 69|pages = 1692–9|last2 = Curtis|first2 = David B.|last3 = Musgrave|first3 = John|last4 = Roensch|first4 = Fred|last5 = Roach|first5 = Jeff|last6 = Rokop|first6 = Don|issue = 9|pmid = 21639292}}</ref><ref>{{cite journal|doi =10.1016/S0016-7037(98)00282-8|title =Nature's uncommon elements: plutonium and technetium|first4 =Jan|last4 =Cramer|first3 =Paul|last3 =Dixon|first2 =June|date=1999|last2 =Fabryka-Martin|last1=Curtis|first1=D.|journal=Geochimica et Cosmochimica Acta|volume =63|pages =275|bibcode=1999GeCoA..63..275C|issue =2|url =https://digital.library.unt.edu/ark:/67531/metadc704244/}}</ref>

===Curium=== 
The first entirely synthetic element to be made was [[curium]], synthesized in 1944 by [[Glenn T. Seaborg]], [[Ralph A. James]], and [[Albert Ghiorso]] by bombarding [[plutonium]] with [[alpha particle]]s.<ref>Krebs, Robert E. [https://books.google.com/books?id=yb9xTj72vNAC&pg=PA322 The history and use of our earth's chemical elements: a reference guide], Greenwood Publishing Group, 2006, {{ISBN|0-313-33438-2}} p. 322</ref><ref>{{cite book|title = The New Chemistry: A Showcase for Modern Chemistry and Its Applications|first = Nina|last = Hall|publisher = Cambridge University Press|date = 2000|pages = [https://archive.org/details/newchemistry00hall/page/8 8]–9|isbn = 978-0-521-45224-3|url = https://archive.org/details/newchemistry00hall|url-access = registration}}</ref>

===Eight others===
Synthesis of [[americium]], [[berkelium]], and [[californium]] followed soon. [[Einsteinium]] and [[fermium]] were discovered by a team of scientists led by [[Albert Ghiorso]] in 1952 while studying the composition of [[radioactive]] debris from the detonation of the first hydrogen bomb.<ref>{{cite journal | doi=10.1021/cen-v081n036.p174 | title=Einsteinium and Fermium | year=2003 | last1=Ghiorso | first1=Albert | journal=Chemical & Engineering News Archive | volume=81 | issue=36 | pages=174–175 }}</ref> The isotopes synthesized were einsteinium-253, with a half-life of 20.5 days, and [[fermium-255]], with a half-life of about 20 hours. The creation of [[mendelevium]], [[nobelium]], and [[lawrencium]] followed.

===Rutherfordium and dubnium===  
During the height of the [[Cold War]], teams from the [[Soviet Union]] and the United States independently created [[rutherfordium]] and [[dubnium]]. The naming and credit for synthesis of these elements remained [[Transfermium Wars|unresolved for many years]], but eventually, shared credit was recognized by [[IUPAC]]/[[IUPAP]] in 1992. In 1997, IUPAC decided to give dubnium its current name, honoring the city of [[Dubna]] where the Russian team worked since American-chosen names had already been used for many existing synthetic elements, while the name ''rutherfordium'' (chosen by the American team) was accepted for element 104.

===The last thirteen=== 
Meanwhile, the American team had created [[seaborgium]], and the next six elements had been created by a German team: [[bohrium]], [[hassium]], [[meitnerium]], [[darmstadtium]], [[roentgenium]], and [[copernicium]]. Element 113, [[nihonium]], was created by a Japanese team; the last five known elements, [[flerovium]], [[moscovium]], [[livermorium]], [[tennessine]], and [[oganesson]], were created by Russian–American collaborations and complete the seventh row of the periodic table.

==List of synthetic elements==

The following elements do not occur naturally on Earth. All are [[transuranium element]]s and have atomic numbers of 95 and higher.

{| class="sortable wikitable"
|-
! Element name !! Chemical<br />Symbol !! Atomic<br />Number !! First definite<br />synthesis
|-
| [[Americium]] || Am || 95 || 1944
|-
| [[Curium]] || Cm || 96 || 1944
|-
| [[Berkelium]] || Bk || 97 || 1949
|-
| [[Californium]] || Cf || 98 || 1950
|-
| [[Einsteinium]]  || Es || 99 || 1952
|-
| [[Fermium]] || Fm || 100 || 1952
|-
| [[Mendelevium]] || Md || 101 || 1955
|-
| [[Nobelium]] || No || 102 || 1965
|-
| [[Lawrencium]] || Lr || 103 || 1961
|-
| [[Rutherfordium]] || Rf || 104 || 1969 (USSR and US) *
|-
| [[Dubnium]] || Db || 105 || 1970 (USSR and US) *
|-
| [[Seaborgium]] || Sg || 106 || 1974
|-
| [[Bohrium]] || Bh || 107 || 1981
|-
| [[Hassium]] || Hs || 108 || 1984
|-
| [[Meitnerium]] || Mt || 109 || 1982
|-
| [[Darmstadtium]] || Ds || 110 || 1994
|-
| [[Roentgenium]] || Rg || 111 || 1994
|-
| [[Copernicium]] || Cn || 112 || 1996
|-
| [[Nihonium]] || Nh || 113 || 2003–04
|-
| [[Flerovium]] || Fl || 114 || 1999
|-
| [[Moscovium]] || Mc || 115 || 2003
|-
| [[Livermorium]] || Lv || 116 || 2000
|-
| [[Tennessine]] || Ts || 117 || 2009
|-
| [[Oganesson]] || Og || 118 || 2002
|-
|colspan=4| * ''Shared credit for discovery.''
|}

==Other elements usually produced through synthesis==
All elements with [[atomic number]]s 1 through 94 occur naturally at least in trace quantities, but the following elements are often produced through synthesis.

{| class="sortable wikitable"
! Element name !! Chemical<br />symbol !! Atomic<br />number !! First definite<br />discovery !! Discovery<br>in nature
|-
| [[Technetium]]‡ || Tc || 43 || 1937 || 1962
|-
| [[Promethium]]‡ || Pm || 61 || 1945 || 1965<ref>{{Ullmann|volume=31|page=188|last1=McGill|first1=Ian|contribution=Rare Earth Elements|doi=10.1002/14356007.a22_607}}</ref>
|-
| [[Polonium]]  || Po || 84 ||| 1898||style="background:red;"|
|-
| [[Astatine]]‡ || At || 85 || 1940 || 1943
|-
| [[Francium]] || Fr || 87 || 1939||style="background:red;"|
|-
| [[Radium]] || Ra || 88 || 1898||style="background:red;"|
|-
| [[Actinium]] || Ac || 89 || 1902||style="background:red;"|
|-
| [[Protactinium]] || Pa || 91 || 1913||style="background:red;"|
|-
| [[Neptunium]]‡ || Np || 93 || 1940 || 1952
|-
| [[Plutonium]]‡ || Pu || 94 || 1940 ||1941–42<ref>{{cite journal | last=Seaborg | first=Glenn T. | last2=Perlman | first2=Morris L. | title=Search for Elements 94 and 93 in Nature. Presence of 94<sup>239</sup> in Pitchblende<sup>1</sup> | journal=Journal of the American Chemical Society | publisher=American Chemical Society (ACS) | volume=70 | issue=4 | year=1948 | issn=0002-7863 | doi=10.1021/ja01184a083 | pages=1571–1573}}</ref>
|}

‡ These five elements were discovered through synthesis before being found in nature.

==References==
{{Reflist}}

==External links==
*{{cite web|url=http://www.britannica.com/EBchecked/topic/181416/einsteinium-Es|title=einsteinium (Es) - chemical element|website=Britannica.com|access-date=23 May 2017}}
*{{cite web|url=http://www.britannica.com/EBchecked/topic/374759/mendelevium-Md|title=mendelevium (Md) - chemical element|website=Britannica.com|access-date=23 May 2017}}
*{{cite web|url=http://encyclopedia2.thefreedictionary.com/synthetic+elements|title=synthetic elements|website=Encyclopedia2.thefreedictionary.com|access-date=23 May 2017}}
*{{cite web|url=http://education.jlab.org/itselemental/ele100.html|title=It's Elemental - The Element Fermium|website=Education.jlab.org|access-date=23 May 2017}}
*{{cite web |last1=Kulkarni |first1=Mayuri |title=A Complete List of Man-made Synthetic Elements |url=https://sciencestruck.com/synthetic-elements |website=ScienceStuck |date=15 June 2009 |access-date=15 May 2019}}

{{DEFAULTSORT:Synthetic Element}}
[[Category:Nuclear physics]]
[[Category:Synthetic elements| ]]
[[Category:Lists of chemical elements]]