Difference between revisions of "Decay chain"
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| − | A '''decay chain''', also called a '''radioactive series''', is a sequence of [[nuclide]]s in which each nuclide transforms into the next by [[radioactive decay]] until a stable nuclide is reached. There are three "classical" decay chains, which describe the decay of the naturally-occuring [[actinoid]]s; a fourth long decay chain has become extinct in natural sources, but is known from artificially-produced radionuclides. Shorter decay chains describe the decay of the [[transfermium element]]s and lighter non-actinoid radionuclides. | + | {{TOCright}} |
| + | A '''decay chain''', also called a '''radioactive series''', is a sequence of [[nuclide]]s in which each nuclide transforms into the next by [[radioactive decay]] until a stable nuclide is reached.<ref>{{GoldBookRef|title=decay chain|file=D01537|accessdate=2011-04-18}}.</ref> There are three "classical" decay chains, which describe the decay of the naturally-occuring [[actinoid]]s; a fourth long decay chain has become extinct in natural sources, but is known from artificially-produced radionuclides.<ref>{{citation | first = Glenn T. | last = Seaborg | authorlink = Glenn T. Seaborg | title = The Neptunium (4n + 1) Radioactive Family | journal = Chem. Eng. News | year = 1948 | volume = 26 | issue = 26 | pages = 1902–6 | doi = 10.1021/cen-v026n026.p1902}}.</ref> Shorter decay chains describe the decay of the [[transfermium element]]s and lighter non-actinoid radionuclides. | ||
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| + | The principle of a decay chain comes from the [[radioactive displacement law]], deduced in 1913 by [[Kasimir Fajans|Fajans]],<ref name="Fajans1">{{citation | first = Kasimir | last = Fajans | authorlink = Kasimir Fajans | title = Die radioaktiven Umwandlungen und das periodische System der Elemente | journal = Ber. Dtsch. Chem. Ges. | year = 1913 | volume = 46 | pages = 422–39 | doi = 10.1002/cber.19130460162}}. [http://www.chemteam.info/Chem-History/Fajans-Isotope.html Translated excerpt]</ref><ref>{{citation | first = K. | last = Fajans | authorlink = Kasimir Fajans | journal = Phys. Z. | year = 1913 | volume = 14 | pages = 131–36}}. {{citation | first = K. | last = Fajans | authorlink = Kasimir Fajans | journal = Phys. Z. | year = 1913 | volume = 14 | pages = 136–42}}. {{citation | first = K. | last = Fajans | authorlink = Kasimir Fajans | journal = Radium | year = 1913 | volume = 10 | pages = 61}}.</ref> [[Frederick Soddy|Soddy]]<ref>{{citation | first = Frederick | last = Soddy | authorlink = Frederick Soddy | title = The Radio-elements and the Periodic Law | journal = Chem. News | year = 1913 | volume = 107 | pages = 97–99 | url = http://web.lemoyne.edu/~giunta/soddycn.html}}.</ref><ref>{{citation | first = Frederick | last = Soddy | authorlink = Frederick Soddy | title = Radioactivity | journal = Annu. Rep. Prog. Chem. | year = 1913 | volume = 10 | pages = 262–88 | doi = 10.1039/AR9131000262}}.</ref> and [[Alexander Russell|Russell]].<ref>{{citation | first = Alexander S. | last = Russell | authorlink = Alexander Russell | title = The periodic system and the radio-elements | journal = Chem. News | year = 1913 | volume = 107 | pages = 49–52}}.</ref> The original version of the law, which describes the most common forms of radioactive decay, is that | ||
| + | *[[alpha decay]] leads to a nuclide with an [[atomic number]] two lower than the decaying nuclide, and a [[mass number]] four lower; | ||
| + | *[[beta decay]]<ref group="note">This description applies to β<sup>−</sup> decay, which was the only type of [[beta decay]] known in 1913.</ref> leads to a nuclide with the same mass number as the decaying nuclide but with an atomic number one higher. | ||
| + | The discovery (1914) of a difference in [[atomic weight]] between [[lead]] samples from [[thorium]] and [[uranium]] minerals,<ref>{{citation | first1 = Frederick | last1 = Soddy | authorlink1 = Frederick Soddy | first2 = Henry | last2 = Hyman | title = The atomic weight of lead from ceylon thorite | journal = J. Chem. Soc., Trans. | year = 1914 | volume = 105 | pages = 1402–8 | doi = 10.1039/CT9140501402}}.</ref><ref>{{citation | first1 = Theodore W. | last1 = Richards | authorlink1 = Theodore W. Richards | first2 = Max E. | last2 = Lembert | title = The Atomic Weight of Lead of Radioactive Origin | journal = J. Am. Chem. Soc. | year = 1914 | volume = 36 | issue = 7 | pages = 1329–44 | doi = 10.1021/ja02184a001}}.</ref> as predicted by Fajans,<ref name="Fajans1"/> was conclusive proof of the corresponding decay chains.<ref>{{citation | first = Oswald U. | last = Anders | title = The place of isotopes in the periodic table: The 50th anniversary of the Fajans–Soddy displacement laws | journal = J. Chem. Educ. | year = 1964 | volume = 41 | issue = 10 | pages = 522 | doi = 10.1021/ed041p522}}.</ref><ref>{{citation | first = George B. | last = Kauffman | title = The atomic weight of lead of radioactive origin: A confirmation of the concept of isotopy and the group displacement laws. Part I | journal = J. Chem. Educ. | year = 1982 | volume = 59 | issue = 1 | pages = 3 | doi = 10.1021/ed059p3}}. {{citation | first = George B. | last = Kauffman | title = The atomic weight of lead of radioactive origin: A confirmation of the concept of isotopy and the group displacement laws. Part II | journal = J. Chem. Educ. | year = 1982 | volume = 59 | issue = 2 | pages = 119 | doi = 10.1021/ed059p119}}.</ref> | ||
==Actinoid decay chains== | ==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'' = 4''n'', or 4''n''+1, etc. for all the nuclides in the chain. | ||
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| + | ===Thorium (4''n'') series=== | ||
| + | {{main|Thorium series}} | ||
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| + | ===Neptunium (4''n''+1) series=== | ||
| + | {{main|Neptunium series}} | ||
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| + | ===Uranium (4''n''+2) series=== | ||
| + | {{main|Uranium series}} | ||
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===Actinium (4''n''+3) series=== | ===Actinium (4''n''+3) series=== | ||
| − | + | {{main|Actinium series}} | |
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==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
- alpha decay leads to a nuclide with an atomic number two lower than the decaying nuclide, and a mass number four lower;
- beta decay[note 1] leads to a nuclide with the same mass number as the decaying nuclide but with an atomic number one higher.
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
- ↑ This description applies to β− decay, which was the only type of beta decay known in 1913.
References
- ↑ 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).
- ↑ Seaborg, Glenn T. The Neptunium (4n + 1) Radioactive Family. Chem. Eng. News 1948, 26 (26), 1902–6. DOI: 10.1021/cen-v026n026.p1902.
- ↑ 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
- ↑ Fajans, K. Phys. Z. 1913, 14, 131–36. Fajans, K. Phys. Z. 1913, 14, 136–42. Fajans, K. Radium 1913, 10, 61.
- ↑ Soddy, Frederick The Radio-elements and the Periodic Law. Chem. News 1913, 107, 97–99, <http://web.lemoyne.edu/~giunta/soddycn.html>.
- ↑ Soddy, Frederick Radioactivity. Annu. Rep. Prog. Chem. 1913, 10, 262–88. DOI: 10.1039/AR9131000262.
- ↑ Russell, Alexander S. The periodic system and the radio-elements. Chem. News 1913, 107, 49–52.
- ↑ Soddy, Frederick; Hyman, Henry The atomic weight of lead from ceylon thorite. J. Chem. Soc., Trans. 1914, 105, 1402–8. DOI: 10.1039/CT9140501402.
- ↑ 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.
- ↑ 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.
- ↑ 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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