Synthetic element

Source: Wikipedia, the free encyclopedia.
  Synthetic elements
  Rare radioactive natural elements; often produced artificially
  Common radioactive natural elements

A synthetic element is one of 24 known

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: 43Tc, 61Pm, 85At, 93Np, and 94Pu, though are sometimes classified as synthetic alongside exclusively artificial elements.[2] The first, technetium, was created in 1937.[3] 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.[4]

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

neutron absorption.[7]

Atomic mass for natural elements is based on weighted average abundance of natural isotopes in Earth's crust and atmosphere. For synthetic elements, there is no "natural isotope abundance". Therefore, for synthetic elements the total nucleon count (protons plus neutrons) 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

product of spontaneous fission of 238U, or from neutron capture in molybdenum—but technetium is present naturally in red giant stars.[13][14][15][16]

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 particles.[17][18]

Eight others

Synthesis of

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

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 elements and have atomic numbers of 95 and higher.

Element name Chemical
Symbol		 Atomic
Number		 First definite
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
* Shared credit for discovery.

Other elements usually produced through synthesis

All elements with atomic numbers 1 through 94 occur naturally at least in trace quantities, but the following elements are often produced through synthesis.

Element name Chemical
Symbol		 Atomic
Number		 First definite
discovery		 Discovery in nature
Technetium Tc 43 1937 1962
Promethium Pm 61 1945 1965[20]
Polonium Po 84 1898
Astatine At 85 1940 1943
Francium Fr 87 1939
Radium Ra 88 1898
Actinium Ac 89 1902
Protactinium Pa 91 1913
Neptunium Np 93 1940 1952
Plutonium Pu 94 1940 1941–42[21]

Technetium, promethium, astatine, neptunium, and plutonium were discovered through synthesis before being found in nature.

References

  1. ^ Kulkarni, Mayuri (15 June 2009). "A Complete List of Man-made Synthetic Elements". ScienceStuck. Retrieved 15 May 2019.
  2. ^ See periodic table here for example.
  3. ^ "WebElements Periodic Table » Technetium » historical information". www.webelements.com. Webelements. Retrieved 7 November 2019.
  4. ^ Bradford, Alina (8 December 2016). "Facts About Plutonium". LiveScience. Retrieved 16 May 2019.
  5. ^ Redd, Nola (November 2016). "How Was Earth Formed?". Space.com. Retrieved 16 May 2019.
  6. ^ "Synthetic elements". Infoplease. Retrieved 16 May 2019.
  7. ^ Kulkarni, Mayuri (15 June 2009). "A Complete List of Man-made Synthetic Elements". ScienceStuck. Retrieved 16 May 2019.
  8. ^ Helmenstine, Anne Marie. "Technetium or Masurium Facts". ThoughtCo. Retrieved 15 May 2019.
  9. ^ "Technetium decay and its cardiac application". Khan Academy. Retrieved 15 May 2019.
  10. doi:10.1088/1674-1137/abddae
    .
  11. ^ Stewart, Doug. "Technetium Element Facts". Chemicool. Retrieved 15 May 2019.
  12. ^ Bentor, Yinon. "Periodic Table: Technetium". Chemical Elements. Retrieved 15 May 2019.
  13. ISBN 978-0-8493-0485-9
    .
  14. PMID 17782983
    .
  15. PMID 21639292
    .
  16. doi:10.1016/S0016-7037(98)00282-8
    .
  17. ISBN 0-313-33438-2
    p. 322
  18. ISBN 978-0-521-45224-3
    .
  19. doi:10.1021/cen-v081n036.p174
    .
  20. ISBN 978-3527306732
    .
  21. ISSN 0002-7863
    .

External links
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