![]() ![]() When a mixture of trace amounts of radon-222 and fluorine gas is heated to approximately 400 ☌ (752 ☏), a nonvolatile radon fluoride is formed. ![]() All the isotopes decay into stable end-products of helium and isotopes of heavy metals, usually lead. Radioactive isotopes having masses ranging from 204 through 224 have been identified, the longest-lived of these being radon-222, which has a half-life of 3.82 days. Giesel and French physicist André-Louis Debierne. Radon-219 (actinon 3.92-second half-life), which is associated with actinium, was found independently in 1904 by German chemist Friedrich O. Owens and British scientist Ernest Rutherford, who noticed that some of the radioactivity of thorium compounds could be blown away by breezes in the laboratory. Radon-220 (thoron 51.5-second half-life) was first observed in 1899 by American scientist Robert B. The name radon is sometimes reserved for this isotope to distinguish it from the other two natural isotopes, called thoron and actinon, because they originate in the thorium and the actinium series, respectively. ![]() Dorn, radon-222 (3.823-day half-life), the longest-lived isotope, arises in the uranium series. Discovered in 1900 by German chemist Friedrich E. Natural radon consists of three isotopes, one from each of the three natural radioactive-disintegration series (the uranium, thorium, and actinium series). Such tubes of radon have been used for radiation therapy and radiography. The tube of gas is a source of penetrating gamma rays, which come mainly from one of radon’s decay products, bismuth-214. Every few days, the accumulated radon is pumped off, purified, and compressed into a small tube, which is then sealed and removed. Typically, a supply of radium is kept in a glass vessel in an aqueous solution or in the form of a porous solid from which the radon can readily flow. Radon levels are highest in homes built over geological formations that contain uranium mineral deposits.Ĭoncentrated samples of radon are prepared synthetically for medical and research purposes. Indeed, radon is now thought to be the greatest cause of lung cancer among nonsmokers in the United States. Exposure to high concentrations of this radon and its daughters over the course of many years can greatly increase the risk of developing lung cancer. The decay of radon produces radioactive “daughters” ( polonium, bismuth, and lead isotopes) that can be ingested from well water or can be absorbed in dust particles and then breathed into the lungs. The gas can accumulate in the air of poorly ventilated houses. Radioactive decay of uranium in minerals, especially granite, generates radon gas that can diffuse through soil and rock and enter buildings through basements (radon has a higher density than air) and through water supplies derived from wells (radon has a significant solubility in water). SpaceNext50 Britannica presents SpaceNext50, From the race to the Moon to space stewardship, we explore a wide range of subjects that feed our curiosity about space!ġ18 Names and Symbols of the Periodic Table Quizīy the late 1980s, naturally occurring radon gas had come to be recognized as a potentially serious health hazard.Learn about the major environmental problems facing our planet and what can be done about them! ![]() Saving Earth Britannica Presents Earth’s To-Do List for the 21st Century.100 Women Britannica celebrates the centennial of the Nineteenth Amendment, highlighting suffragists and history-making politicians.COVID-19 Portal While this global health crisis continues to evolve, it can be useful to look to past pandemics to better understand how to respond today.Student Portal Britannica is the ultimate student resource for key school subjects like history, government, literature, and more.This Time in History In these videos, find out what happened this month (or any month!) in history.#WTFact Videos In #WTFact Britannica shares some of the most bizarre facts we can find.Demystified Videos In Demystified, Britannica has all the answers to your burning questions.Britannica Classics Check out these retro videos from Encyclopedia Britannica’s archives.Britannica Explains In these videos, Britannica explains a variety of topics and answers frequently asked questions. ![]()
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