Difference between revisions of "Decay chain"

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===Actinium  (4''n''+3) series===
 
===Actinium  (4''n''+3) series===
 
{{main|Actinium series}}
 
{{main|Actinium series}}
{| class="wikitable" style="text-align:center;"
 
|-
 
| colspan=2 | [[Uranium-235]]<br/>(α, 7.04{{e|8}} a)
 
|-
 
| colspan=2 | [[Thorium-231]]<br/>(β<sup>−</sup>, 25.52 h)
 
|-
 
| colspan=2 | [[Protactinium-231]]<br/>(α, 3.276{{e|4}} a)
 
|-
 
| colspan=2 | [[Actinium-227]]<br/>(21.772 a)
 
|-
 
| α, 1.38% || β<sup>−</sup>, 98.62%
 
|-
 
| [[Francium-223]]<br/>(22.00 min) || [[Thorium-227]]<br/>(α, 18.68 d)
 
|-
 
|}
 
  
 
==Notes and references==
 
==Notes and references==

Latest revision as of 08:57, 18 April 2011

A decay chain, also called a radioactive series, is a sequence of nuclides in which each nuclide transforms into the next by radioactive decay until a stable nuclide is reached.[1] There are three "classical" decay chains, which describe the decay of the naturally-occuring actinoids; a fourth long decay chain has become extinct in natural sources, but is known from artificially-produced radionuclides.[2] Shorter decay chains describe the decay of the transfermium elements and lighter non-actinoid radionuclides.

The principle of a decay chain comes from the radioactive displacement law, deduced in 1913 by Fajans,[3][4] Soddy[5][6] and Russell.[7] The original version of the law, which describes the most common forms of radioactive decay, is that

The discovery (1914) of a difference in atomic weight between lead samples from thorium and uranium minerals,[8][9] as predicted by Fajans,[3] was conclusive proof of the corresponding decay chains.[10][11]

Actinoid decay chains

Because alpha decay changes the mass number by four, while beta decay does not change the mass number at all, all the nuclides in a decay chain have the same value of mod 4(A), and the chains can be distinguished as those where A = 4n, or 4n+1, etc. for all the nuclides in the chain.

Thorium (4n) series

Neptunium (4n+1) series

Uranium (4n+2) series

Actinium (4n+3) series

Notes and references

Notes

  1. This description applies to β decay, which was the only type of beta decay known in 1913.

References

  1. decay chain, <http://goldbook.iupac.org/D01537.html> (accessed 18 April 2011), Compendium of Chemical Terminology Internet edition; International Union of Pure and Applied Chemistry (IUPAC).
  2. Seaborg, Glenn T. The Neptunium (4n + 1) Radioactive Family. Chem. Eng. News 1948, 26 (26), 1902–6. DOI: 10.1021/cen-v026n026.p1902.
  3. 3.0 3.1 Fajans, Kasimir Die radioaktiven Umwandlungen und das periodische System der Elemente. Ber. Dtsch. Chem. Ges. 1913, 46, 422–39. DOI: 10.1002/cber.19130460162. Translated excerpt
  4. Fajans, K. Phys. Z. 1913, 14, 131–36. Fajans, K. Phys. Z. 1913, 14, 136–42. Fajans, K. Radium 1913, 10, 61.
  5. Soddy, Frederick The Radio-elements and the Periodic Law. Chem. News 1913, 107, 97–99, <http://web.lemoyne.edu/~giunta/soddycn.html>.
  6. Soddy, Frederick Radioactivity. Annu. Rep. Prog. Chem. 1913, 10, 262–88. DOI: 10.1039/AR9131000262.
  7. Russell, Alexander S. The periodic system and the radio-elements. Chem. News 1913, 107, 49–52.
  8. Soddy, Frederick; Hyman, Henry The atomic weight of lead from ceylon thorite. J. Chem. Soc., Trans. 1914, 105, 1402–8. DOI: 10.1039/CT9140501402.
  9. Richards, Theodore W.; Lembert, Max E. The Atomic Weight of Lead of Radioactive Origin. J. Am. Chem. Soc. 1914, 36 (7), 1329–44. DOI: 10.1021/ja02184a001.
  10. Anders, Oswald U. The place of isotopes in the periodic table: The 50th anniversary of the Fajans–Soddy displacement laws. J. Chem. Educ. 1964, 41 (10), 522. DOI: 10.1021/ed041p522.
  11. Kauffman, George B. The atomic weight of lead of radioactive origin: A confirmation of the concept of isotopy and the group displacement laws. Part I. J. Chem. Educ. 1982, 59 (1), 3. DOI: 10.1021/ed059p3. Kauffman, George B. The atomic weight of lead of radioactive origin: A confirmation of the concept of isotopy and the group displacement laws. Part II. J. Chem. Educ. 1982, 59 (2), 119. DOI: 10.1021/ed059p119.

External links

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