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For glow in the dark paint.Used in treating cancer because of the gamma rays it gives off. | Atomic Number: | 88 | Atomic Symbol: | Ra | | Atomic Weight: | 226.0254 | Electron Configuration: | 2-8-18-8-2 | | Shells: | 2,8,18,32,18,8,2 | Filling Orbital: | 7s2 | | Melting Point: | 700oC | Boiling Point: | 1737oC | | Description: | Silver white metal. Intensely radioactive. |
History(L. radius, ray) Radium was discovered in 1898 by Mme. Curie in
the pitchblende or uraninite of North Bohemia, where it occurs. There is about 1
g of radium in 7 tons of pitchblende. The element was isolated in 1911 by Mme.
Curie and Debierne by; the electrolysis of a solution of pure radium chloride,
employing a mercury cathode; on distillation in an atmosphere of hydrogen this
amalgam yielded the pure metal. Originally, radium was obtained from the rich
pitchblende ore found in Joachimsthal, Bohemia. The carnotite sands of Colorado
furnish some radium, but richer ores are found in the Republic of Zaire and the
Great Lake region of Canada.
OccurenceRadium is present in all uranium minerals, and could be extracted, if
desired, from the extensive wastes of uranium processing.
Large uranium deposits are located in Ontario, New Mexico, Utah, Australia,
and elsewhere.
Radium is obtained commercially as the bromide and chloride; it is doubtful
if any appreciable stock of the isolated element now exists.
PropertiesThe pure metal is brilliant white when freshly prepared, but blackens on
exposure to air, probably due to formation of the nitride.
It exhibits luminescence, as do its slats; it decomposes in water and is
somewhat more volatile than barium.
It is a member of the alkaline-earth group of metals.
Radium imparts a carmine red color to a flame.
Radium emits alpha, beta, and gamma rays and when mixed with beryllium
prodcue neutrons.
One gram of 226Ra undergoes 3.7 x 10^10 disintegrations per s.
IsotopesThe curie is defined as that amount of radioactivity which has
the same disintegration rate as 1 g of 226Ra. Twenty five isotopes are now
known; radium 226, the common isotope, has a half-life of 1600 years.
UsesOne gram of radium produces about 0.0001 ml (stp) of emanation, or radon
gas, per day.
This is purged from the radium and sealed in minute tubes, which are used in
the treatment of cancer and other diseases.
Radium is used in the producing of self-luminous paints, neutron sources,
and in medicine for the treatment of disease.
Some of the more recently discovered radioisotopes, such as 60Co, are now
being used in place of radium.
Some of these sources are much more powerful, and others are safer to use.
Radium loses about 1% of its activity in 25 years, being transformed into
elements of lower atomic weight.
Lead is a final product of disintegration.
Stored radium should be ventillated to prevent build-up of radon.
HandlingInhalation, injection, or body exposure to radium can cause
cancer and other body disorders. The maximum permissible burder in the total
body for 226Ra is 7400 becquerel.
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