radon (Rn), chemical element, a heavy radioactive gas of Group 18 (noble gases) of the periodic table, generated by the radioactive decay of radium. (Radon was originally called radium emanation.) Radon is a colourless gas, 7.5 times heavier than air and more than 100 times heavier than hydrogen.

Who created radon?

The German chemist Friedrich Ernst Dorn has been credited with the discovery of radon in 1900. He discovered the new gas, which he referred to as radium emanation, while studying the decay chain of radium. Radium was discovered just two years prior by the Nobel Prize-winning scientist Marie Curie.

Is uranium a radon?

The primary source of radon is from uranium in soils and rocks and in groundwater. Over time, uranium decays into radium, which then decays directly into radon.