Stable isotope

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Stable isotopes are chemical isotopes that are not radioactive (to current knowledge). Stable isotopes of the same element have the same chemical characteristics and therefore behave almost identically. The mass differences, due to a difference in the number of neutrons, result in partial separation of the light isotopes from the heavy isotopes during chemical reactions (isotope fractionation). For example, the difference in mass between the two stable isotopes of hydrogen, 1H (1 proton, no neutron, also known as protium) and 2H (1 proton, 1 neutron, also known as deuterium) is almost 100%. Therefore, a significant fractionation will occur.

Commonly analysed stable isotopes include oxygen, carbon, nitrogen, hydrogen and sulfur. These isotope systems have been under investigation for many years as they are relatively simple to measure. Recent advances in mass spectrometry (ie. multiple-collector inductively coupled plasma mass spectrometry) now enable the measurement of heavier stable isotopes, such as iron, copper, zinc, molybdenum, etc.

Stable isotopes have been used in botanical and plant biological investigations for many years, and more and more ecological and biological studies are finding stable isotopes (mostly carbon, nitrogen and oxygen) to be extremely useful. Other workers have used oxygen isotopes to reconstruct historical atmospheric temperatures, making them important tools for climate research.

Most of naturally occurring isotopes are stable; however, few tens of them are radioactive with very long half-lives. The half life of a nuclide should be comparable with the Earth's age (4.5 billions years) to be present in the natural isotopic composition of a chemical element. The lowest half life times of such isotopes are more than 700 millions years (235U). Many isotopes which are presumed to be stable (i.e. no radioactivity has been observed for them) are predicted to be radioactive with extremely long half-lives (sometimes as high as 1018 years or more). If the predicted half life falls into an experimentally accessible range, such isotopes have a chance to move from the list of stable nuclides to the radioactive category, once their activity is observed. Good examples are bismuth-209 and tungsten-180 which have been recently (2003) found to be alpha-active.

Stable isotope fractionation

There are three types of isotope fractionation:

List of stable isotopes

There are exactly 80 elements which have at least 1 stable isotope. As of September 2007, there were 244 known stable isotopes. Tin has 10 stable isotopes, more than any other element. Xenon is the only element which has 9 stable isotopes. There is no element with exactly 8 stable isotopes. Mononuclidic elements are those that have a single isotope (stable or very long-lived) in their natural abundance. Every element from hydrogen to lead has at least one stable isotope with the exceptions of technetium and promethium; elements with more than 82 protons only have radioactive isotopes, although they can still occur naturally because their half-lives are of an order of magnitude not much less than that of the time since the death of a nearby star, or because they occur in a decay chain of another radioactive isotope with such a half-life. It wasn't until 2003 that bismuth-209 was shown to be radioactive.[1] All stable isotopes are the ground states of nuclei, excluding tantalum-180m, which is the excited level (the ground state of this nucleus is radioactive), but its decay is extremely strongly forbidden by spin-parity selection rules.

  1. Hydrogen-1
  2. Hydrogen-2
  3. Helium-3
  4. Helium-4
  5. Lithium-6
  6. Lithium-7
  7. Beryllium-9
  8. Boron-10
  9. Boron-11
  10. Carbon-12
  11. Carbon-13
  12. Nitrogen-14
  13. Nitrogen-15
  14. Oxygen-16
  15. Oxygen-17
  16. Oxygen-18
  17. Fluorine-19
  18. Neon-20
  19. Neon-21
  20. Neon-22
  21. Sodium-23
  22. Magnesium-24
  23. Magnesium-25
  24. Magnesium-26
  25. Aluminium-27
  26. Silicon-28
  27. Silicon-29
  28. Silicon-30
  29. Phosphorus-31
  30. Sulfur-32
  31. Sulfur-33
  32. Sulfur-34
  33. Sulfur-36
  34. Chlorine-35
  35. Chlorine-37
  36. Argon-36
  37. Argon-38
  38. Argon-40
  39. Potassium-39
  40. Potassium-41
  41. Calcium-40
  42. Calcium-42
  43. Calcium-43
  44. Calcium-44
  45. Calcium-46
  46. Scandium-45
  47. Titanium-46
  48. Titanium-47
  49. Titanium-48
  50. Titanium-49
  51. Titanium-50
  52. Vanadium-51
  53. Chromium-52
  54. Chromium-53
  55. Chromium-54
  56. Manganese-55
  57. Iron-54
  58. Iron-56
  59. Iron-57
  60. Iron-58
  61. Cobalt-59
  62. Nickel-58
  63. Nickel-60
  64. Nickel-61
  65. Nickel-62
  66. Nickel-64
  67. Copper-63
  68. Copper-65
  69. Zinc-64
  70. Zinc-66
  71. Zinc-67
  72. Zinc-68
  73. Zinc-70
  74. Gallium-69
  75. Gallium-71
  76. Germanium-70
  77. Germanium-72
  78. Germanium-73
  79. Germanium-74
  80. Arsenic-75
  81. Selenium-74
  82. Selenium-76
  83. Selenium-77
  84. Selenium-78
  85. Selenium-80
  86. Bromine-79
  87. Bromine-81
  88. Krypton-80
  89. Krypton-82
  90. Krypton-83
  91. Krypton-84
  92. Krypton-86
  93. Rubidium-85
  94. Strontium-84
  95. Strontium-86
  96. Strontium-87
  97. Strontium-88
  98. Yttrium-89
  99. Zirconium-90
  100. Zirconium-91
  101. Zirconium-92
  102. Zirconium-94
  103. Niobium-93
  104. Molybdenum-92
  105. Molybdenum-94
  106. Molybdenum-95
  107. Molybdenum-96
  108. Molybdenum-97
  109. Molybdenum-98
    Technetium - No stable isotopes
  110. Ruthenium-96
  111. Ruthenium-98
  112. Ruthenium-99
  113. Ruthenium-100
  114. Ruthenium-101
  115. Ruthenium-102
  116. Ruthenium-104
  117. Rhodium-103
  118. Palladium-102
  119. Palladium-104
  120. Palladium-105
  121. Palladium-106
  122. Palladium-108
  123. Palladium-110
  124. Silver-107
  125. Silver-109
  126. Cadmium-106
  127. Cadmium-108
  128. Cadmium-110
  129. Cadmium-111
  130. Cadmium-112
  131. Cadmium-114
  132. Indium-113
  133. Tin-112
  134. Tin-114
  135. Tin-115
  136. Tin-116
  137. Tin-117
  138. Tin-118
  139. Tin-119
  140. Tin-120
  141. Tin-122
  142. Tin-124
  143. Antimony-121
  144. Antimony-123
  145. Tellurium-122
  146. Tellurium-123
  147. Tellurium-124
  148. Tellurium-126
  149. Iodine-127
  150. Xenon-124
  151. Xenon-126
  152. Xenon-128
  153. Xenon-129
  154. Xenon-130
  155. Xenon-131
  156. Xenon-132
  157. Xenon-134
  158. Xenon-136
  159. Caesium-133
  160. Barium-132
  161. Barium-134
  162. Barium-135
  163. Barium-136
  164. Barium-137
  165. Barium-138
  166. Lanthanum-139
  167. Cerium-138
  168. Cerium-140
  169. Praseodymium-141
  170. Neodymium-142
  171. Neodymium-143
  172. Neodymium-145
  173. Neodymium-146
  174. Neodymium-148
    Promethium - No stable isotopes
  175. Samarium-144
  176. Samarium-150
  177. Samarium-152
  178. Samarium-154
  179. Europium-153
  180. Gadolinium-154
  181. Gadolinium-155
  182. Gadolinium-156
  183. Gadolinium-157
  184. Gadolinium-158
  185. Gadolinium-160
  186. Terbium-159
  187. Dysprosium-156
  188. Dysprosium-158
  189. Dysprosium-160
  190. Dysprosium-161
  191. Dysprosium-162
  192. Dysprosium-163
  193. Dysprosium-164
  194. Holmium-165
  195. Erbium-162
  196. Erbium-164
  197. Erbium-166
  198. Erbium-167
  199. Erbium-168
  200. Erbium-170
  201. Thulium-169
  202. Ytterbium-168
  203. Ytterbium-170
  204. Ytterbium-171
  205. Ytterbium-172
  206. Ytterbium-173
  207. Ytterbium-174
  208. Ytterbium-176
  209. Lutetium-175
  210. Hafnium-176
  211. Hafnium-177
  212. Hafnium-178
  213. Hafnium-179
  214. Hafnium-180
  215. Tantalum-180m
  216. Tantalum-181
  217. Tungsten-182
  218. Tungsten-183
  219. Tungsten-184
  220. Tungsten-186
  221. Rhenium-185
  222. Osmium-187
  223. Osmium-188
  224. Osmium-189
  225. Osmium-190
  226. Osmium-192
  227. Iridium-191
  228. Iridium-193
  229. Platinum-192
  230. Platinum-194
  231. Platinum-195
  232. Platinum-196
  233. Platinum-198
  234. Gold-197
  235. Mercury-198
  236. Mercury-199
  237. Mercury-200
  238. Mercury-201
  239. Mercury-202
  240. Mercury-204
  241. Thallium-203
  242. Thallium-205
  243. Lead-206
  244. Lead-207
  245. Lead-208

See also

References

  1. "WWW Table of Radioactive Isotopes".

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