Radon is a chemical element wi seembol Rn an atomic nummer 86. It is a radioactive, colourless, odorless, tasteless[2] noble gas, occurrin naiturally as an indirect decay product o uranium or thorium. Its maist stable isotope, 222Rn, haes a hauf-life o 3.8 days. Radon is ane o the densest substances that remains a gas unner normal condeetions. It is the anly gas unner normal condeetions that anly haes radioactive isotopes, an is considered a heal hazard due tae its radioactivity an aa. Intense radioactivity haes an aa hindered chemical studies o radon an anly a few compoonds are kent.
Radon, 86RnRadon |
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Pronunciation | (RAY-don) |
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Appearance | colourless gas |
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Mass number | [222] |
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Radon in the periodic cairt |
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Atomic nummer (Z) | 86 |
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Group | group 18 (noble gases) |
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Period | period 6 |
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Block | p-block |
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Element category | Noble gas |
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Electron confeeguration | [Xe] 4f14 5d10 6s2 6p6 |
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Electrons per shell | 2, 8, 18, 32, 18, 8 |
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Pheesical properties |
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Phase at STP | gas |
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Meltin pynt | 202 K (−71 °C, −96 °F) |
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Bylin pynt | 211.5 K (−61.7 °C, −79.1 °F) |
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Density (at STP) | 9.73 g/L |
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whan liquid (at b.p.) | 4.4 g/cm3 |
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Creetical pynt | 377 K, 6.28[1] MPa |
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Heat o fusion | 3.247 kJ/mol |
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Heat o vapourisation | 18.10 kJ/mol |
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Molar heat capacity | 5R/2 = 20.786 J/(mol·K) |
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Vapour pressur
P (Pa)
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1
|
10
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100
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1 k
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10 k
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100 k
|
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at T (K)
|
110
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121
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134
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152
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176
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211
|
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Atomic properties |
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Oxidation states | 0, +2, +6 |
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Electronegativity | Pauling scale: 2.2 |
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Covalent radius | 150 pm |
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Van der Waals radius | 220 pm |
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Spectral lines o radon |
Ither properties |
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Creestal structur | face-centred cubic (fcc) |
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Thermal conductivity | 3.61 m W/(m·K) |
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Magnetic orderin | non-magnetic |
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CAS Nummer | 10043-92-2 |
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History |
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Diskivery | Friedrich Ernst Dorn (1898) |
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First isolation | William Ramsay an Robert Whytlaw-Gray (1910) |
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Main isotopes o radon |
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| references |