ra·don (r  d n)n. Symbol Rn A colorless, radioactive, inert gaseous element formed by the radioactive decay of radium. It is used as a radiation source in radiotherapy and to produce neutrons for research. Its most stable isotope is Rn 222 with a half-life of 3.82 days. Atomic number 86; melting point -71°C; boiling point -61.8°C; specific gravity (solid) 4. See Table at element. |
radon [ˈreɪdɒn]
n
(Chemistry / Elements & Compounds) a colourless radioactive element of the rare gas group, the most stable isotope of which, radon-222, is a decay product of radium. It is used as an alpha particle source in radiotherapy. Symbol: Rn; atomic no.: 86; half-life of 222Rn: 3.82 days; valency: 0; density: 9.73 kg/m3; melting pt.: -71°C; boiling pt.: -61.7°C
[from radium + -on]
| radon (rdn) Symbol Rn A colorless, odorless, radioactive element in the noble gas group. It is produced by the radioactive decay of radium and occurs in minute amounts in soil, rocks, and the air near the ground. Radon is used as a source of radiation for the treatment of cancer and other diseases. Its most stable isotope is Rn 222 with a half-life of 3.82 days. Atomic number 86; melting point -71°C; boiling point -61.8°C; specific gravity (solid) 4. See Periodic Table. |
ThesaurusLegend: Synonyms Related Words Antonyms
| Noun | 1. |  radon - a radioactive gaseous element formed by the disintegration of radium; the heaviest of the inert gasses; occurs naturally (especially in areas over granite) and is considered a hazard to healthchemical element, element - any of the more than 100 known substances (of which 92 occur naturally) that cannot be separated into simpler substances and that singly or in combination constitute all matter |
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