'Radon' definitions:

Definition of 'radon'

From: WordNet
noun
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 health [syn: radon, Rn, atomic number 86]

Definition of 'Radon'

From: GCIDE
  • 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 Rn. It has an atomic number of 86. The radon isotope produced by decay of radium has an atomic weight of 222.017, and this isotope decays by alpha emission with a half-life of 3.82 days. Numerous other isotopes have been observed, all radioactive and all having half-lives shorter than that of radon-222. Radon was discovered by M. and Mme. Curie, of Paris, in their studies of the radioactive substances in pitchblende. Radon was originally called radium emanation or exradio. [PJC]

Definition of 'radon'

From: GCIDE
  • Noble \No"ble\, a. [Compar. Nobler; superl. Noblest.] [F. noble, fr. L. nobilis that can be or is known, well known, famous, highborn, noble, fr. noscere to know. See know.]
  • 1. Possessing eminence, elevation, dignity, etc.; above whatever is low, mean, degrading, or dishonorable; magnanimous; as, a noble nature or action; a noble heart. [1913 Webster]
  • Statues, with winding ivy crowned, belong To nobler poets for a nobler song. --Dryden. [1913 Webster]
  • 2. Grand; stately; magnificent; splendid; as, a noble edifice. [1913 Webster]
  • 3. Of exalted rank; of or pertaining to the nobility; distinguished from the masses by birth, station, or title; highborn; as, noble blood; a noble personage. [1913 Webster]
  • Note: Noble is used in the formation of self-explaining compounds; as, noble-born, noble-hearted, noble-minded. [1913 Webster]
  • Noble gas (Chem.), a gaseous element belonging to group VIII of the periodic table of elements, not combining with other elements under normal reaction conditions; specifically, helium, neon, argon, krypton, xenon, or radon; also called inert gas.
  • Noble metals (Chem.), silver, gold, and platinum; -- so called from their resistance to oxidation by air and to dissolution by acids. Copper, mercury, aluminium, palladium, rhodium, iridium, and osmium are sometimes included. [1913 Webster]
  • Syn: Honorable; worthy; dignified; elevated; exalted; superior; sublime; great; eminent; illustrious; renowned; stately; splendid; magnificent; grand; magnanimous; generous; liberal; free. [1913 Webster]

Definition of 'Radon'

From: Elements
  • Symbol: Rn
  • Atomic number: 86
  • Atomic weight: (222)
  • Colorless radioactive gaseous element, belongs to the noble gases. Of the twenty known isotopes, the most stable is Rn-222 with a half-life of 3.8 days. Formed by the radioactive decay of Radium-226. Radon itself decays into polonium. Used in radiotherapy. As a noble gas, it is effectively inert, though radon fluoride has been synthesized. First isolated in 1908 by Ramsey and Gray.