Discovery date : 1900
Discovered by: Friedrich Ernst Dorn
Origin of the name: The name is derived from radium,
as it was first detected as an emission from radium during radioactive decay.
Allotropes : -
~>RADON is a chemical element with symbol Rn and atomic number 86. It is a radioactive, colorless, odorless, tasteless noble gas.
| FACT BOX | |||
| Group | 18 | Melting point | −71°C, −96°F, 202 K |
| Period | 6 | Boiling point | −61.7°C, −79.1°F, 211.5 K |
| Block | d | Density (g cm−3) | 0.009074 |
| Atomic number | 86 | Relative atomic mass | [222] |
| State at 20°C | Gas | Key isotopes | 211Rn220Rn222Rn |
| Electron configuration | [Xe] 4f145d106s26p6 | CAS number | 10043-92-2 |
| ChemSpider ID | 23240 | ChemSpider is a free chemical structure database | |
In 1899, Ernest Rutherford and Robert B. Owens detected a radioactive gas being released by thorium. That same year, Pierre and Marie Curie detected a radioactive gas emanating from radium. In1900, Friedrich Ernst Dorn at Halle, Germany, noted that a gas was accumulating inside ampoules of radium. They were observing radon. That from radium was the longer-lived isotope radon-222 which has a half-life 3.8 days, and was the same isotope which the Curies has observed. The radon that Rutherford detected was radon-220 with a half-life of 56 seconds.
In 1900, Rutherford devoted himself to investigating the new gas and showed that it was possible to condense it to a liquid. In 1908, William Ramsay and Robert Whytlaw-Gray at University College, London, collected enough radon to determine its properties and reported that it was the heaviest gas known.