Radon is a chemical element wi seembol Rn an atomic nummer 86. It is a radioactive, colourless, odorless, tastelessnoble gas, occurrin naiturally as an indirect decay product o uranium or thorium. Its maist stable isotope, 222Rn, haes a hauf-life o 3.8 days. Radon is ane o the densest substances that remains a gas unner normal condeetions. It is the anly gas unner normal condeetions that anly haes radioactive isotopes, an is considered a heal hazard due tae its radioactivity an aa. Intense radioactivity haes an aa hindered chemical studies o radon an anly a few compoonds are kent.