Radon

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

Radon,  ₈₆Rn

General properties
Pronunciation	/ˈreɪdɒn/ ​(RAY-don)
Appearance	colorless gas
Mass number	222 (most stable isotope)
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
Atomic number (Z)	86
Group	group 18 (noble gases)
Period	period 6
Block	p-block
Element category	noble gas
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
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)
Main isotopes of radon
Iso­tope Abun­dance Half-life (t1/2) Decay mode Pro­duct 210Rn syn 2.4 h α 206Po 211Rn syn 14.6 h ε 211At α 207Po 222Rn trace 3.8235 d α 218Po 224Rn syn 1.8 h β− 224Fr

Radon is element 86 on the periodic table. Its symbol is Rn.

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.

Related pages

• List of common elements
• Periodic table