Radon-222

Radon-222, 222Rn
General
Symbol222Rn
Namesradon-222, 222Rn, Rn-222,
Radium emanation
Protons (Z)86
Neutrons (N)136
Nuclide data
Natural abundanceTrace
Half-life (t1/2)3.8215 d[1]
Isotope mass222.0175763[2] Da
Spin0
Parent isotopes226Ra (α)
Decay products218Po
Decay modes
Decay modeDecay energy (MeV)
Alpha decay5.5904[2]
Isotopes of radon
Complete table of nuclides

Radon-222 (222Rn, Rn-222, historically radium emanation or radon) is the most stable isotope of radon, with a half-life of approximately 3.8 days. It is transient in the decay chain of primordial uranium-238 and is the immediate decay product of radium-226. Radon-222 was first observed in 1899, and was identified as an isotope of a new element several years later. In 1957, the name radon, formerly the name of only radon-222, became the name of the element. Owing to its gaseous nature and high radioactivity, radon-222 is one of the leading causes of lung cancer.[3]

  1. ^ Audi, G.; Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S. (2017). "The NUBASE2016 evaluation of nuclear properties" (PDF). Chinese Physics C. 41 (3): 030001. Bibcode:2017ChPhC..41c0001A. doi:10.1088/1674-1137/41/3/030001.
  2. ^ a b Wang, M.; Audi, G.; Kondev, F. G.; Huang, W. J.; Naimi, S.; Xu, X. (2017). "The AME2016 atomic mass evaluation (II). Tables, graphs, and references" (PDF). Chinese Physics C. 41 (3): 030003-1–030003-442. doi:10.1088/1674-1137/41/3/030003.
  3. ^ Cite error: The named reference EPA02 was invoked but never defined (see the help page).