My Saved Article
| Atomic Number: | 11 | Atomic Symbol: | Na | | Atomic Weight: | 22.98977 | Electron Configuration: | 2-8-1 | | Shells: | 2,8,1 | Filling Orbital: | 3s1 | | Melting Point: | 97.8oC | Boiling Point: | 882.9oC | | Uses: | Salt, medicine, agriculture, photography and also to cool nuclear
reactors |
History(English, soda; Medieval Latin, sodanum, headache remedy) Long
recognized in compounds, sodium was first isolated by Sir Humphrey Davy in 1807
by electrolysis of caustic soda.
SourcesSodium is present in fair abundance in the sun and stars. The D
lines of sodium are among the most prominent in the solar spectrum. Sodium is
the fourth most abundant element on earth, comprising about 2.6% of the earth's
crust; it is the most abundant of the alkali group of metals.
It is now obtained commercially by the electrolysis of absolutely dry fused
sodium chloride. This method is much cheaper than that of electrolyzing sodium
hydroxide, as was used several years ago.
CompoundsThe most common compound is sodium chloride, but it occurs in
many other minerals, such as soda niter, cryolite, amphibole, zeolite, etc.
PropertiesSodium, avery reactive element, is never found free in
nature. Sodium is a soft, bright, silvery metal which floats on water,
decomposing it with the evolution of hydrogen and the formation of the
hydroxide. It may or may not ignite spontaneously on water, depending on the
amount of oxide and metal exposed to the water. It normally does not ignite in
air at temperatures below 115C.
UsesMetallic sodium is vital in the manufacture of esters and in the
preparation of organic compounds. The metal may be used to improve the structure
of certain alloys, to descale metal, and to purify molten metals.
An alloy of sodium with potassium, NaK, is also an important heat transfer
agent.
CompoundsSodium compounds are important to the paper, glass, soap,
textile, petroleum, chemical, and metal industries. Soap is generally a sodium
salt of certain fatty acids. The importance of common salt to animal nutrition
has been recognized since prehistoric times.
Among the many compounds that are of the greatests industrial importance are
common salt (NaCl), soda ash (Na2CO3), baking soda (NaHCO3), caustic soda
(NaOH), Chile saltpeter (NaNO3), di- and tri-sodium phosphates, sodium
thiosulfate (hypo, Na2S2O3) . 5H2O), and borax (Na2B4O7 . 10H2O).
IsotopesThirteen
isotopes of sodium are recognized.
CostSmaller quantities of sodium, such as a kilogram, cost far more, in the range of
$165/kg. This is partially due to the cost of shipping hazardousmaterial.HandlingSodium metal should be handled with great care. It cannot be
maintained in an inert atmosphere and contact with water and other substances
with which sodium reacts should be avoided.
|
|
|