Radon

Radon is a chemical element in the periodic table. It is element 86 on the periodic table and its symbol is Rn. It is an odorless, tasteless noble gas. It is quite radioactive and can decay very quickly. 27 isotopes of Radon are known today. The most stable of them has a half life of about 3.8 days. 

 Chemistry 
Radon is a gas and is part of the group known as the noble gases.  It does not react with other elements, so it is found pure. Radon is radioactive, meaning that it can give off harmful rays.  Some people have high levels of radon in their houses, and this can be very dangerous.  A lot of radon can get stuck in the basement of old houses, and so people end up breathing it in.  It gets stuck in the lungs and has been known to cause cancer.  There are groups that try to make sure there is no dangerous radon in houses.

It can occur naturally on the Earth but is a very small amount. As elements like Thorium and Uranium decay, some of that gets turned into Radon.

Radon can cause lung cancer and is the second most popular cause of lung cancer straight after smoking.

 History 
Radon was the fifth radioactive element to be discovered, in 1899 by Ernest Rutherford and Robert B. Owens at McGill University in Montreal, after uranium, thorium, radium, and polonium. In 1899, Pierre and Marie Curie saw that the gas given off by radium remained radioactive for a month. Later that year, Rutherford and Owens noticed different types of them when trying to measure radiation from thorium oxide.

 Uses 
It is sometimes used in radiation therapy. However, it is very dangerous to use.left|thumb|An electron shell diagram for radon. Note the eight electrons in the outer shell.

Related pages
List of common elements
Periodic table

 References 

Category:Noble gases
Category:Carcinogens