Is Radon a noble gas?

The below article talks about radon, noble gases, whether radon is a noble gas, along with some frequently asked questions concerning radon and radon poisoning. 

Is Radon a noble gas?

Radon is a radioactive, colorless, odorless, and tasteless noble gas, occurring through the decay of radium, uranium, and thorium. Since it is a noble gas, it is chemically not active and can only combine with other compounds under extreme circumstances. It is the heaviest known gas and is a health hazard due to its radioactivity that causes severe health effects to those exposed. 

What are noble gases?

Noble gases make up Group 18 of the periodic table, and there are 6 of them that occur naturally, namely: Helium (He), Neon (Ne), Argon (Ar), Krypton (Kr), Xenon (Xe), and radioactive Radon (Rn). There were also previously known as inert gases or aerogens. Under normal or standard conditions, noble gases are tasteless, non-flammable, odorless, colorless, monoatomic, with really low chemical reactivity. They do not react unless they are subjected to extreme conditions and remain gaseous under normal circumstances. They stay liquid in a really short temperature range. 

They were initially called rare or inert gases because it was thought that these compounds were quite rare. However, research into the case found that these gases were quite common across the surface of the planet, and were not as rare as previously considered. In the case of being named inert gases, since they did not form any reactions under standard conditions, they were considered as chemically not active, and thus inert; this condition however has been proven false much later, when it was found that noble gases do react under extreme conditions. 

In the periodic table, every noble gas (Group 18 elements) is wedged between electronegative groups (Group 17- halogens) and electropositive groups (Group 1- alkali metals). Group 17 elements need to add electrons to achieve an octet and thus become negative ions, whereas Group 1 elements need to lose electrons to become positive ions. Noble gases are quite often used in various sectors, especially since they do not cause any reactions under standard conditions, and their total indifference to oxygen makes them a much-utilized option in terms of various activities. For example, helium and argon are often used for cutting, welding, metal refining processes, etc. Other uses of noble gases include the following:

  • Helium is used for filling buoyant balloons 
  • An oxygen-helium mixture can be used to treat asthma 
  • Argon provides an inert atmosphere that can be used in welding elements like titanium, aluminum, stainless steel, magnesium, etc.
  • Argon is also used in the production of titanium 
  • Small amounts of argon are used in germanium and silicon crystals used for electric light bulbs, transistors, etc. 
  • Helium is used to attain lower temperatures required for lasers. 
  • Helium is used in nuclear reactors as a cooling gas, used as a flow gas for liquid chromatography protocols, used in airships, etc. 
  • Xenon and krypton are used in the flash units of photographing equipment as it generates bright bouts of light. It has also been traditionally used in lighthouses. 
  • Neon, xenon, and krypton are used to produce different colored lights. 
  • Neon is used in sodium vapor lamps 
  • Krypton is used for miners’ helmets or caps
  • Radon is used for multiple research purposes

About Radon 

Discovered by a German chemist, Friedrich Ernst Dorn in 1900; Radon has an atomic number of 86, which means there are 86 protons in its nucleus. It is chemically denoted as ‘Rn’, average atomic mass is 222, in room temperatures, it remains at gaseous state, melting point is -71 ℃, and boiling point is -61.7 ℃. There are 3 naturally occurring isotopes: Radon-219, Radon-220, and Radon-222; 33 isotopes that are unstable. The most common isotope is Rn-222 (Pedersen T., 2018). 

Radon is a naturally occurring radioactive gas, that could have severe impacts on physical health, including the onset of lung cancer. Usually, radon is found in high concentrations in homes and workplaces, and since its tasteless, odorless, and colorless, it is usually not identified until there is a diagnosis of radon poisoning for someone exposed to high levels of radon. Radon is one of the leading causes in the world for lung cancer and has been found to contribute anywhere between 3% to 14% to all lung cancer cases in a country, depending on the national average of radon levels, and national radon emissions or strategies set in place. 

Radon is produced during the natural radioactive decay of uranium, which can be found in rocks or soils. It can also be found in different water bodies occasionally. Radon has the capability to escape from the ground and latch onto air molecules, where it would decay further and cause the emission of radioactive particles. Radon is capable of entering our bodies via breathing and is deposited in our nasal pathways and lung tissue, where prolonged exposure and deposit formation could cause the initiation of cancer in the person. 

Outdoor, radon can be diluted quickly and is only present in smaller concentrations that do not pose a threat to health, however, indoors, with limited ventilation, there is a possibility of increasing radon concentration and exposure, which could lead to severe health effects. Especially in places such as mines, caves, water treatment facilities, older buildings, etc. can have increased radon concentrations. Given the physical and chemical properties of radon, inhabitants and employees of such places could be potentially exposed to high levels of radon, which could cause them long-term distress and chronic health conditions. 

Symptoms of Radon Poisoning

Radon poisoning builds up eventually, and may not show symptoms until quite late. Usually, either during the diagnosis of cancer caused by radon poisoning or when you’re on the verge of a diagnosis. Therefore, it is always advised to keep an eye out for the below symptoms of radon poisoning that you may experience (NRD, n.d.): 

  • Persistent cough 
  • Changes in voice and increased hoarseness
  • Wheezing 
  • Respiratory difficulties 
  • Coughing up blood
  • Chest pain
  • Increased frequencies of bronchitis or pneumonia 
  • Loss of appetite
  • Weight loss
  • Fatigue 

Frequently Asked Questions (FAQs): Is radon a noble gas?

Are radon test kits reliable?

Radon is a hidden danger to many, due to which it is highly recommended to conduct periodical radon check-ups. Radon can be monitored using self-test kits or by professionals. Self-tests for radon are of two types, a short-term test or a long-term test. Studies have shown that more accurate readings are shown by the long-term tests that measure radon in your house during an approximate period of 90 days. 

When do radon poisoning symptoms show up?

One of the main reasons that radon poisoning is as dangerous as it is lethal is because radon has the capability to build and form deposits in our body, and symptoms of radon poisoning may not appear until too late. It is also to be noted that initial symptoms of radon poisoning may look like the flu, due to which they may be dismissed and treated as generic flu or allergy. It has also been found that radon symptoms may show up late and aren’t diagnosed as radon poisoning until cancer has been identified or is close to being identified. This is one of the main reasons that several state governments and experts recommend periodical checking of indoor air quality levels so that tabs are being kept and mitigation strategy can be taken up as and when the problem arises, rather than waiting until physical health has deteriorated severely. 

Which radon test kits are best?

Here is a link to an article that compares different kinds of at-home radon test kits. It is always best to remember that long-term radon test kits are more accurate and provide users with a clearer understanding of the degree of mitigation strategies that may be required.


Dale T. (2022, January 27). The best radon test kits of 2022. Bob Villa. Viewed on 02-02-2022. 

Pedersen T. (2018, August 01). Facts about Radon. Live Science. Viewed on 02-02-2022. 

National Radon Defense (NRD). (n.d.). Radon Symptoms. Viewed on 02-02-2022.