Radon

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 222017 and this isotope decays by alpha emission with a half life of 382 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