Radon In this paper I will discuss the element called Radon. I will explain how and when this element was discovered, its' physical characteristics, the natural environment of the element and the abundance in which it occurs. In addition, I will describe why Radon is important to humans, and other interesting facts related to this element. Radon has the symbol Rn. Its atomic number is 86 and its atomic weight is 222. The shell configuration is 2,8,18,32,18,8. Radon's most stable isotope is Rn 222 with a half-life of 3.82 days. An isotope is one of two or more atoms that have the same atomic number, but have different atomic weights and mass numbers (The America Heritage Dictionary