Atomic Number: 86
Atomic Weight: -222.0
Element Type: Noble Gas
Crystal Structure: Cubic Face Centered
Melting Point: -71.0°C = -95.8°F = 202.15
Boiling Point: -61.7°C = -79.06°F = 211.45
Critical Temp: 104.0°C = 219.2°F = 377.15
Atomic Radius: 1.34 Å (Å = Angstrom =
Covalent Radius: Å
(From radium; called niton at first, L. nitens, shining)
The element was discovered in1900 by Dorn, who called it
radium emanation. In 1908 Ramsay and Gray, who named it
niton,isolated the element and determined its density, finding
it to be the heaviest known gas.It is essentially inert
and occupies the last place in the zero group of gases in
thePeriodic Table. Since 1923, it has been called radon.
Properties Of Radon
At ordinary temperatures radon is a colourless gas. When
cooled below the freezing point, radon exhibits a brilliant
phosphorescence which becomes yellow as the temperature
is lowered and orange-red at the temperature of liquid air.
The main hazard is from inhalation of the element and its
decay products which are collected on dust in the air. Recently,
radon buildup in homes from the surrounding soil and rocks
has become a safety issue and some areas around the world
test homes for radon gas. It is the heaviest known gas.
Radon is present in some spring waters.
Here is a brief summary of the isolation of radon.
Radon is present to a very small trace extent in the atmosphere
and in principle could be obtained as a byproduct from the
liquefaction and separation of air. However as only small
quantities are ever needed in practice, and because of its
short half life (the longest life isotope has a half life
of less than 4 days), such quantities as are required are
isolated through collection from the radioactive decay of
an isotope of radium (226Ra, half life 1599 years).
226Ra 222Rn + 4He
This method gives 0.64 cm3 of radon gas per gram of radium