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Radon (Rn): Fun Facts and Information About the Element


What is the symbol? Rn
What is the atomic number? 86
What is the atomic weight? 222
What is the melting point in Celsius? -71
What is the boiling point in Celsius? -62
What is the density (g/cm3)? 9.73
What year was it discovered? 1900
Oxidation states 2
Electronegativity 2.2 (Pauling scale)
Crystal structure face-centered cubic
Magnetic ordering non-magnetic
Who discovered the element? Friedrich Ernst Dorn
What group is the element in? 18
What is the electron configuration? [Xe] 4f14 5d10 6s2 6p6
What is the ionization energy? 10.7485
What element category is it in? Noble gases

Concentration Scale

1 Bq/m3
Radon concentration at the shores of large oceans is typically 1 Bq/m3.
Radon trace concentration above oceans or in Antarctica can be lower than 0.1 Bq/m3.

10 Bq/m3
Mean continental concentration in the open air: 10 to 30 Bq/m3.
Based on a series of surveys, the global mean indoor radon concentration is estimated to be 39 Bq/m3.

100 Bq/m3
Typical indoor domestic exposure. Most countries have adopted a radon concentration of 200–400 Bq/m3 for indoor air as an Action or Reference Level. If testing shows levels less than 4 picocuries radon per liter of air (160 Bq/m3), then no action is necessary. A cumulated exposure of 230 Bq/m3 of radon gas concentration during a period of 1 year corresponds to 1 WLM.

1,000 Bq/m3
Very high radon concentrations (>1000 Bq/m3) have been found in houses built on soils with a high uranium content and/or high permeability of the ground. If levels are 20 picocuries radon per liter of air (800 Bq/m3) or higher, the home owner should consider some type of procedure to decrease indoor radon levels.

10,000 Bq/m3
The “Working Level” in uranium mines corresponds to a 7000 Bq/m3 concentration.

The concentration in the air at the (unventilated) Gastein Healing Gallery averages 43 kBq/m3 (about 1.2 nCi/L) with maximal value of 160 kBq/m3 (about 4.3 nCi/L).[49]

100,000 Bq/m3
About 100,000 Bq/m3 (2.7 nCi/L) was measured in Stanley Watras’s basement

1,000,000 Bq/m3
Concentrations reaching 1,000,000 Bq/m3 can be found in unventilated uranium mines.

Where is Radon Found?

Radon is present in some spring waters, such as those at Hot Springs, Arkansas.

What is Radon Used For?

Radon is still produced for therapeutic use by a few hospitals by pumping it from a radium source and sealing it in minute tubes, called seeds or needles, for application to patient.