Page 42 - Curriculum Visions Dynamic Book

of an electric spark such as a flash
of lightning or from a spark plug in a car engine, it forms nitric oxide (NO) and then the dioxide (NO2). Oxides of nitrogen are poisonous. Nitrogen dioxide is one of the main pollutants of the atmosphere and a producer of ground-level ozone.
Discovery
Nitrogen was discovered by Daniel Rutherford in Scotland in 1772, who originally called it noxious air because it is the main part of the air but, unlike oxygen, does not support life.
Technology
Nitrogen is mainly used in the form of ammonia for fertilisers. It also goes into explosives such as nitroglycerin.
It is widely used to keep air away
from food during food preparation. Freeze–drying is done in an atmosphere of nitrogen. Liquid nitrogen can expel oil from underground oilfields or also play
a safety role by filling tanks that normally contain explosive liquids.
Geology
Few minerals contain nitrogen.The main nitrate mineral is saltpetre (sodium nitrate, NaNO3), a soluble mineral.
Biology
Nitrogen forms part of one of the world’s most important natural cycles, the nitrogen cycle. It is an essential part of many molecules that are made from amino acids. Animals get nitrogen for their tissues
by eating vegetable or animal proteins. Nitrogen is fixed from the atmosphere
by bacteria living on the roots of some plants such as peas, usually called legumes.
Nitrogen is added to fields by farmers wanting to get increased yields. Some nitrogen seeps from the fields into rivers and can cause pollution. Some nitrogen compounds such as cyanide are highly poisonous. Nitrogen oxides from vehicle combustion help produce acid rain and can be an irritant.
Nitrogen group elements
Another term for the group 5 elements in the Periodic Table, which include nitrogen (N), phosphorus (P), arsenic (As), antimony (Sb) and bismuth (Bi).
 Nitric oxide is a colourless gas.When mixed with air, it reacts with oxygen to produce brown nitrogen dioxide.
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For more on nitrogen, see Volume 11: Nitrogen and Phosphorus in the Elements set.