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Radon-222 (222 Rn, 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 .
The most stable isotope is 222 Rn with a half-life of 3.8235 days, which decays into 218 Po. Six isotopes of radon, ... 217 At, 218 At, 223 Ra, 224 Ra, 225 Ra, ...
Radium (88 Ra) has no stable or nearly stable isotopes, and thus a standard atomic weight cannot be given. The longest lived, and most common, isotope of radium is 226 Ra with a half-life of 1600 years. 226 Ra occurs in the decay chain of 238 U (often referred to as the radium series). Radium has 34 known isotopes from 201 Ra to 234 Ra.
Radium-226 decays by alpha-particle emission, producing radon that collects over samples of radium-226 at a rate of about 1 mm 3 /day per gram of radium; equilibrium is quickly achieved and radon is produced in a steady flow, with an activity equal to that of the radium (50 Bq). Gaseous 222 Rn (half-life of about four days) escapes from the ...
Radioactive isotope table "lists ALL radioactive nuclei with a half-life greater than 1000 years", incorporated in the list above. The NUBASE2020 evaluation of nuclear physics properties F.G. Kondev et al. 2021 Chinese Phys. C 45 030001. The PDF of this article lists the half-lives of all known radioactives nuclides.
All other 27 known radium isotopes have half-lives under two hours, and the majority have half-lives under a minute. [2] Of these, 221 Ra (half-life 28 s) also occurs as a 237 Np daughter, and 220 Ra and 222 Ra would be produced by the still-unobserved double beta decay of natural radon isotopes. [13]
Radon-222 is formed as part of the uranium series i.e. the normal radioactive decay chain of uranium-238 that terminates in lead-206. Uranium has been present since the Earth was formed, and its most common isotope has a very long half-life (4.5 billion years), which is the time required for one-half of uranium to break down. Thus, uranium and ...
The hazardous elements found in NORM are radium 226, 228 and radon 222 and also daughter products from these radionuclides. ... The half-life for radium 226 is ...