Nitrogen, symbol N, gaseous element that makes up the largest portion of the earth's atmosphere.  
The atomic number of nitrogen is 7.  Nitrogen is in group 15 (or Va) of the periodic table.

Nitrogen was discovered by the British physician Daniel Rutherford in 1772 and recognized as an
elemental gas by the French chemist, Antoine Laurent Lavoiser about 1776.

Nitrogen is a colorless, odorless tasteless, nontoxic gas.  It can be condensed into a colorless
liquid, which can be compressed into a colorless, crystalline solid.  Nitrogen exists in two natural forms,
and four radioactive forms (artificial).  Nitrogen melts at -210.01 degrees C, (-349.02 F), boils at -195.79 C
(320.42 F), and has a density of 1.251 g/liter at 0 C (32 F) and 1 atmosphere pressure.  The atomic weight
of nitrogen is 14.007.

Nitrogen is obtained from the atmosphere by passing air over heated copper of iron.  The oxygen
is removed from the air, leaving nitrogen mixed with inert gases.  Pure nitrogen is obtained by fractional
distillation of liquid air; because liquid nitrogen has a lower boiling point than liquid oxygen, the nitrogen
distills of first an can be collected.

Nitrogen compresses about 4/5ths by volume of the atmosphere.  Nitrogen is inert and serves as a
diluent for oxygen in burning and respiration processes.  It is an important element in plant nutrition;
certain bacteria in the soil convert atmospheric nitrogen into a form, such as nitrate, that can be absorbed by
plants, a process called nitrogen fixation.  Nitrogen in the form of protein is an important constituent of
animal tissue.  The element occurs in the combined state in minerals, of which saltpeter (KNO ) and Chile
saltpeter (NaNO ) are commercially important products.

Nitrogen combines with other elements only at very high temperatures of pressures.  It is
converted to an active form by passing through an electronic discharge at low pressure.  The nitrogen so
produced is very active, combining with alkali metals to form azides; with the vapor of zinc, mercury
cadmium,  and arsenic to form nitrides; and with many hydrocarbons to form hydrocyanic acid and
cyanides, also known as nitriles.  Activated nitrogen returns to ordinary nitrogen in about one minute.

In the combined state nitrogen takes part in many reactions; it forms so many compounds that a
systematic scheme of compounds containing nitrogen in place of oxygen was created by the American
chemist Edward Franklin.  In compounds nitrogen exists in all the valence states between -3 and +5.  
Ammonia, hydrazine, and hydroxylamine represent compounds in which the valence of nitrogen is -3, -2,
and -1, respectively.  Oxides of nitrogen represent nitrogen in all the positive valence states.

Most of the nitrogen used in the chemical industry is obtained by the fractional distillation of
liquid air.  It is then used to synthesize ammonia.  From ammonia produced in this manner, a wide variety
of important chemical products are prepared, including fertilizers, nitric acid, urea, hydrazine, and amines.  
In addition, an ammonia compound is used in the preparation of nitrous oxide (N 0) a colorless gas
popularly known as laughing gas.  Mixed with oxygen, nitrous oxide is used as an anesthetic for some
types of surgery.

Used as a coolant, liquid nitrogen has found widespread application in the field of cryogenics.  
With the recent advent of ceramic materials that become superconductive at the boiling point of nitrogen,
the use of nitrogen as a coolant is increasing.

In conclusion, it seems as if Nitrogen is very helpful in the modern world. It is used in dentists
office's to using it for industrial applications.  Without this element the world would be a little different in
some fields.

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