Radon (Rn) is a chemical element and atomic number (Z) 86, group 18, period 6, atomic mass number 222. The Radon (Rn) is colorless at standard temperature and pressure that is chemically unreactive, but highly radioactive and has a short half life. Radon was sometimes used in hospitals to treat cancer and was produced as needed and delivered in sealed gold needles. (Refer to the Chemical Element; Periodic Table)
