106 Radon Radon is the chemical element of symbol Rn and atomic number 86. It is a rare radioactive gas, belonging to the noble gas series, and is formed as part of three radioactive decay chains that begin with uranium or thorium. Thirty-six radioactive isotopes of radon, with mass number from 193 to 228, have been characterized. The most stable isotope is Rn-222 (half-life of 3.8 days); it is generated naturally by the decay of 238U and emits alpha particles. Rn-220 (half-life of 55.6 seconds) is a natural decay product of thorium and also emits alpha radiation. Because of its radioactivity and unreactivity as a chemical element, radon has few uses and is seldom used in academic research. Radon is responsible for the majority of the mean public exposure to ionizing radiations. It is one ingredient of cigarette. (L1075) 10043-92-2 24857 Rn 0.000000 Radon is a colorless, odorless, tasteless gas. (L1075) 202°K (-71.15°C, -96°F) 211.3°K (−61.85 °C, −79.1 °F) 9.73 kg/m3 (standard temperature and pression) Inhalation (L1075) The ionizing radiation produced by radon causes cellular damage that includes DNA breakage, accurate or inaccurate repair, apoptosis, gene mutations, chromosomal change, and genetic instability. This leads to loss of normal cell and tissue homeostasis, and development of malignancy. Ionizing radiation that does not directly damage DNA can produce reactive oxygen intermediates that directly affect the stability of p53, an important enzyme in cell-cycle regulation, and produce oxidative damage to individual bases in DNA and point mutations by mispairing during DNA replication. (L1836) Exposure to radon can occur from inhalation or dermal contact. It can also enter the body via ingestion if dissolved in water. Radon distributes mainly to the fat. It is not metabolized and may be eliminated in the urine, faeces, or expired air. (L1836) 1, carcinogenic to humans. (L135) Radon has few uses and is seldom used in academic research. Radon gas from natural sources can accumulate in buildings, especially in confined areas such as basements. Radon can be found in some spring waters and hot springs. (L1075) Radon is responsible for the majority of the mean public exposure to ionizing radiations. Due to it's radioactivity, breathing high concentrations of radon can cause lung cancer. According to the United States Environmental Protection Agency, radon could be the second most frequent cause of lung cancer, after cigarette smoking; and radon-induced lung cancer the 6th leading cause of cancer death overall, causing 21,000 lung cancer deaths per year in the United States. (L1075) Exposure to high doses of ionizing radiation results in acute radiation syndrome, which can cause skin burns, hair loss, nausea, vomiting, dizziness, disorientation, low blood pressure, headache, fatigue, weakness, fever, birth defects, illness, infection, and death. (L1837, L1852) Treatment reversing the effects of irradiation is currently not possible. Anaesthetics and antiemetics are administered to counter the symptoms of exposure, as well as antibiotics for countering secondary infections due to the resulting immune system deficiency. (L1852) 2009-03-06T18:58:05Z 2014-12-24T20:21:07Z http://en.wikipedia.org/wiki/Radon 33314 D011886 Radon true [Rn] Rn InChI=1S/Rn InChIKey=SYUHGPGVQRZVTB-UHFFFAOYSA-N 222.0 222.0 Exogenous Gas 23240