Radon

Radon (chemical symbol Rn) is a colorless gas with atomic number 86. It belongs to the group of naturally occurring gases known as noble gases, meaning it does not readily react with other elements. All of its isotopes are radioactive, making it inherently unstable.

Radon occurs naturally in the earth, produced by the gradual decay of uranium and thorium in rocks and soil. Being a gas, it can escape from the ground and accumulate in buildings, particularly in lower areas near the soil surface such as basements, especially when ventilation is poor.

Physical and Chemical Properties

At normal temperature, radon is a colorless, odorless, and tasteless gas. It is the densest of the commonly known gases, which causes it to accumulate in lower areas. The most common isotope, Rn-222, has a half-life of approximately three and a half days and is produced by radium decay. Due to its chemical stability, radon compounds are extremely rare and are produced only in laboratories.

History of Discovery

Radon was identified in the late nineteenth and early twentieth centuries, when scientists were investigating the radioactivity emitted by radium. It was initially given various names, such as niton and emanation, before the name radon became standard.

Health and Indoor Air

Inhalation of radon and its decay products increases the risk of lung cancer. Many countries have established recommended levels for the maximum concentration of radon in indoor air, and measurements called radon testing are performed to determine exposure. Mitigation measures include improving ventilation and sealing cracks in foundations.