Symbol Rn
Atomic Number 86
Atomic Mass 222 g.mol 1
Discovered by Friedrich Ernst Dorn in 1900

Chemical Properties of Radon

Group 18 Melting point −71°C, −96°F, 202 K
Period 6 Boiling point −61.7°C, −79.1°F, 211.5 K
Block p Density (g cm3) 0.009074
Atomic number 86 Relative atomic mass 222
State at 20°C Gas Key isotopes 211Rn, 220Rn, 222Rn
Electron configuration [Xe] 4f145d106s26p6 CAS number 10043-92-2
ChemSpider ID 23240 ChemSpider is a free chemical structure database

What is Radon?

  • Radon was first detected as an emission from the radioactive decay of radium.
  • It has an atomic number of 86 and represented with the symbol Rn in the periodic table.
  • Radon is available in hot springs and some spring water.  Its concentration is commonly measured in becquerel ( Bq ) per cubic meter.
  • In the air, its concentration varies from 1 and 100 Bq per cubic meter. In some places, well water will be rich in Radon. Even rainwater can be extremely radioactive due to the high concentration of the element.

Physical properties of Radon

  • Radon (Rn) is colorless, tasteless, odorless gas at standard pressure and temperature and it is the densest noble gas.
  • At a temperature below its freezing point, it posses a brilliant yellow phosphorescence.
  • It is highly radioactive and chemically unreactive.

Applications and effects of Radon

  • Scientific:
    • Radon is used to track air masses to a limited level.
    • Changes in groundwater radon concentrations help in the prediction of Earthquake.
    • In 1940’s radon is used X-ray sources and for industrial radiography.
  • Medical:
    • A process called Radon hormesis is used to mitigate auto-immune diseases like arthritis.
    • It is used in the treatment of cell damage and cancer.
    • Radon is also used in radiation therapy.

Health effects of Radon

  • Radon occurs mainly in gaseous state and people are mainly exposed to it through breathing air. Exposure to the element through breathing may cause lung disease.
  • The best thing about radon is it will not have harmful effects without actual contact with it.

Practise This Question

Pollution of air is caused due to _______.