Editing Tellurium (section)

===Isotopes===
{{Main|Isotopes of tellurium}}
Naturally occurring tellurium has eight isotopes. Six of those isotopes, <sup>120</sup>Te, <sup>122</sup>Te, <sup>123</sup>Te, <sup>124</sup>Te, <sup>125</sup>Te, and <sup>126</sup>Te, are stable. The other two, <sup>128</sup>Te and <sup>130</sup>Te, are slightly radioactive,<ref name="NUBASE">{{Cite journal| last1 = Audi| first1 = G.|title = The NUBASE Evaluation of Nuclear and Decay Properties| journal = Nuclear Physics A| volume = 729| issue = 1| pages = 3–128|publisher = Atomic Mass Data Center| date = 2003| doi = 10.1016/j.nuclphysa.2003.11.001| bibcode=2003NuPhA.729....3A| last2 = Bersillon| first2 = O.| last3 = Blachot| first3 = J.| last4 = Wapstra| first4 = A. H.| url = http://hal.in2p3.fr/in2p3-00014184}}</ref><ref name="Tellurium 128">{{Cite web|title = WWW Table of Radioactive Isotopes: Tellurium|publisher = Nuclear Science Division, Lawrence Berkeley National Laboratory|date = 2008|url = http://ie.lbl.gov/toi/nuclide.asp?iZA=520128|access-date = 2010-01-16|archive-url = https://web.archive.org/web/20100205101344/http://ie.lbl.gov/toi/nuclide.asp?iZA=520128|archive-date = 2010-02-05|url-status = dead}}</ref><ref>{{cite journal|arxiv=hep-ex/0211015|doi= 10.1103/PhysRevC.67.014323|title= New limits on naturally occurring electron capture of <sup>123</sup>Te|journal= Physical Review C|volume= 67|issue= 1|pages= 014323|year= 2003|last1= Alessandrello|first1= A.|last2= Arnaboldi|first2= C.|last3= Brofferio|first3= C.|last4= Capelli|first4= S.|last5= Cremonesi|first5= O.|last6= Fiorini|first6= E.|last7= Nucciotti|first7= A.|last8= Pavan|first8= M.|last9= Pessina|first9= G.|last10= Pirro|first10= S.|last11= Previtali|first11= E.|last12= Sisti|first12= M.|last13= Vanzini|first13= M.|last14= Zanotti|first14= L.|last15= Giuliani|first15= A.|last16= Pedretti|first16= M.|last17= Bucci|first17= C.|last18= Pobes|first18= C.|bibcode= 2003PhRvC..67a4323A|s2cid= 119523039}}</ref> with extremely long half-lives, including 2.2&nbsp;×&nbsp;10<sup>24</sup> years for <sup>128</sup>Te. This is the longest known half-life among all [[radionuclide]]s<ref>{{Cite web|title=Noble Gas Research |publisher=Laboratory for Space Sciences, Washington University in St. Louis |date=2008 |url=http://presolar.wustl.edu/work/noblegas.html |access-date=2013-01-10 |url-status=dead |archive-url=https://web.archive.org/web/20110928143717/http://presolar.wustl.edu/work/noblegas.html |archive-date=September 28, 2011 }}</ref> and is about 160 [[Orders of magnitude (numbers)#1012|trillion]] (10<sup>12</sup>) times the [[Age of the universe|age of the known universe]].

A further 31 artificial [[radioisotope]]s of tellurium are known, with [[atomic mass]]es ranging from 104 to 142 and with half-lives of 19 days or less. Also, 17 [[nuclear isomer]]s are known, with half-lives up to 154 days. Except for [[beryllium-8]] and beta-delayed alpha emission branches in some lighter [[nuclide]]s, tellurium (<sup>104</sup>Te to <sup>109</sup>Te) is the second lightest element with isotopes known to undergo alpha decay, [[antimony]] being the lightest.<ref name="NUBASE" />

The atomic mass of tellurium ({{val|127.60|u=g·mol<sup>−1</sup>}}) exceeds that of iodine ({{val|126.90|u=g·mol<sup>−1</sup>}}), the next element in the periodic table.<ref name="Emsley">{{Cite book|chapter-url = https://books.google.com/books?id=j-Xu07p3cKwC&pg=PA426|isbn = 978-0-19-850340-8|pages = [https://archive.org/details/naturesbuildingb0000emsl/page/426 426–429]|publisher = Oxford University Press|date = 2003|title = Nature's building blocks: an A-Z guide to the elements|chapter = Tellurium|first = John|last = Emsley|url = https://archive.org/details/naturesbuildingb0000emsl/page/426}}</ref>