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Radon is a chemical element in the periodic table. It is element 86 on the periodic table and its symbol is Rn. It is an odorless, tasteless noble gas. It is quite radioactive and can decay very quickly. 27 isotopes of Radon are known today. The most stable of them has a half life of about 3.8 days.

Chemistry

Radon is a gas and is part of the group known as the noble gases. It does not react with other elements, so it is found pure. Radon is radioactive, meaning that it can give off harmful rays. Some people have high levels of radon in their houses, and this can be very dangerous. A lot of radon can get stuck in the basement of old houses, and so people end up breathing it in. It gets stuck in the lungs and has been known to cause cancer. There are groups that try to make sure there is no dangerous radon in houses.

It can occur naturally on the Earth but is a very small amount. As elements like Thorium and Uranium decay, some of that gets turned into Radon.

Radon can cause lung cancer and is the second most popular cause of lung cancer straight after smoking.

History

Radon was the fifth radioactive element to be discovered, in 1899 by Ernest Rutherford and Robert B. Owens at McGill University in Montreal, after uranium, thorium, radium, and polonium. In 1899, Pierre and Marie Curie saw that the gas given off by radium remained radioactive for a month. Later that year, Rutherford and Owens noticed different types of them when trying to measure radiation from thorium oxide.

Uses

It is sometimes used in radiation therapy. However, it is very dangerous to use.

An electron shell diagram for radon. Note the eight electrons in the outer shell.

Radon, ₀₀Rn

Radon
Pronunciation	/?re?d?n/ ?(RAY-don)
Appearance	colorless gas
Mass number	[222]
Radon in the periodic table
Hydrogen Helium Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury (element) Thallium Lead Bismuth Polonium Astatine Radon Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson Xe ↑ Rn ↓ Og astatine ← radon → francium
Group	group 18 (noble gases)
Period	period 6
Block	p-block
Electron configuration	[Xe] 4f14 5d10 6s2 6p6
Electrons per shell	2, 8, 18, 32, 18, 8
Physical properties
Phase at STP	gas
Melting point	202 K ?(?71 °C, ??96 °F)
Boiling point	211.5 K ?(?61.7 °C, ??79.1 °F)
Density (at STP)	9.73 g/L
when liquid (at b.p.)	4.4 g/cm3
Critical point	377 K, 6.28 MPa
Heat of fusion	3.247 kJ/mol
Heat of vaporization	18.10 kJ/mol
Molar heat capacity	5R/2 = 20.786 J/(mol·K)
Vapor pressure P (Pa) 1 10 100 1 k 10 k 100 k at T (K) 110 121 134 152 176 211
Atomic properties
Oxidation states	0, +2, +6
Electronegativity	Pauling scale: 2.2
Ionization energies	1st: 1037 kJ/mol
Covalent radius	150 pm
Van der Waals radius	220 pm
Spectral lines of radon
Other properties
Natural occurrence	from decay
Crystal structure	?face-centered cubic (fcc)
Thermal conductivity	3.61×10?3  W/(m?K)
Magnetic ordering	non-magnetic
CAS Number	10043-92-2
History
Discovery	Ernest Rutherford and Robert B. Owens (1899)
First isolation	William Ramsay and Robert Whytlaw-Gray (1910)
Isotopes of radon
Main isotopes Decay abun-dance half-life (t1/2) mode pro-duct 210Rn synth 2.4 h α 206Po 211Rn synth 14.6 h ε 211At α 207Po 222Rn trace 3.8235 d α 218Po 224Rn synth 1.8 h β? 224Fr

Related pages

• List of common elements
• Periodic table