radon

A noble gas, of a radioactive nature, present in the atmosphere in small concentrations, whose greatest abundance occurs near the ground, in areas where there is rocky material, such as granite, that releases it into the air as a consequence of the decay of radium, a highly radioactive element. Radon is a colorless, odorless gas, whose atomic mass is 222 and whose chemical symbol is Rn. It is responsible for part of the ionization of the air taking place near the ground, as a consequence of the emission of alpha particles (highly energetic) from its decay.