Radon is a decay product of uranium, which is relatively common in the Earth's crust, but generally concentrated in ore-bearing rocks scattered around the world.
As for the element radium, the name is derived from the Latin word radius=radiation. The suffix on is the same as for the others noble gases (excepting helium).
Radon is a naturally occurring element. It is a noble gas, and is highly unreactive. Radon is a poisonous gas and is the second most common reason people have lung cancer (behind smoking). Most radon...
Radon can cause lung cancer but it is also used in radiation treatments for some times of cancer (ironic, I know); and some people go to Radon spas located in Russia and Central Europe because they...