radium emanation
31Isotopes of radon — There are thirty four known isotopes of radon (Rn). The most stable isotope is 222Rn, which is a decay product (daughter product) of 226Ra, has a half life of 3.823 days and emits alpha particles. 220Rn is a natural decay product of thorium and… …
32Radioactive decay — For particle decay in a more general context, see Particle decay. For more information on hazards of various kinds of radiation from decay, see Ionizing radiation. Radioactive redirects here. For other uses, see Radioactive (disambiguation).… …
33radon — /ray don/, n. Chem. a chemically inert, radioactive gaseous element produced by the decay of radium: emissions produced by outgassing of rock, brick, etc. are a health hazard. Symbol: Rn; at. no.: 86; at. wt.: 222. [1915 20; RAD(IUM) + ON2] * * * …
34Radon — A radioactive element formed as a gas during the breakdown of radium. * * * A gaseous radioactive element, atomic no. 86, resulting from the breakdown of radium; of the isotopes with mass numbers between 198 and 228, only 222Rn is medically… …
35List of chemical element name etymologies — This is the list of etymologies for all chemical element names: Name Symbol Language of origin Word of origin Meaning Symbol origin Description Actinium Ac Greek ἀκτίς (aktis) beam Greek aktinos ἀκτίς, ἀκτῖνος (aktis; aktinos), meaning beam (ray) …
36eman — em·an (emґən) a unit for expressing the concentration of radium emanation in solution: it is the concentration present when one tenth of a millimicrocurie of radium emanation is dissolved in 1 liter of air or water, or 10−10 curie …
37Isotopes du radon — Le radon (Rn) possède 35 isotopes connus, tous radioactifs. Le plus stable d entre eux est le radon 222 (222Rn) avec une demi vie de 3,823 jours. Quatre isotopes, 218Rn, 219Rn, 220Rn et 222Rn, sont présents dans la nature à l état de trace; ils… …
38exradio — Radon Ra don (r[=a] d[o^]n), n. (Chem.) An intensely radioactive gaseous element produced by the radioactive decay of radium 226, which is the main isotope of radium found in pitchblende. Chemically it is an inert noble gas. Its atomic symbol is… …
39Radon — Ra don (r[=a] d[o^]n), n. (Chem.) An intensely radioactive gaseous element produced by the radioactive decay of radium 226, which is the main isotope of radium found in pitchblende. Chemically it is an inert noble gas. Its atomic symbol is Rn. It …
40Noble gas — Group 18 Period 1 2 He 2 …
