Nitrogen is a chemical element with symbol N and atomic number 7. It was first discovered and isolated by Scottish physician Daniel #Rutherford
in 1772. Although Carl Wilhelm Scheele and Henry Cavendish had independently done so at about the same time, Rutherford is generally accorded the credit because his work was published first. The name nitrogène was suggested by French chemist Jean-Antoine-Claude Chaptal in 1790, when it was found that nitrogen was present in nitric acid and nitrates. Antoine Lavoisier suggested instead the name #azote
, from the Greek άζωτικός "no life", as it is an #asphyxiant
gas; this name is instead used in many languages, such as French, Russian, and Turkish, and appears in the English names of some nitrogen compounds such as #hydrazine
is the lightest member of group 15 of the periodic table, often called the pnictogens. The name comes from the Greek πνίγειν "to choke", directly referencing nitrogen's asphyxiating properties. It is a common element in the universe, estimated at about seventh in total abundance in the Milky Way and the Solar System. At standard temperature and pressure, two atoms of the element bind to form dinitrogen, a colourless and odorless diatomic gas with the formula N2. #Dinitrogen
forms about #78
% of Earth's atmosphere, making it the most abundant uncombined element. Nitrogen occurs in all organisms, primarily in #amino
acids (and thus proteins), in the nucleic acids (#DNA
) and in the energy transfer molecule #adenosine
triphosphate. The human body contains about 3% nitrogen by mass, the #fourth
most abundant element in the body after oxygen, carbon, and hydrogen. The nitrogen cycle describes movement of the element from the air, into the #biosphere
and organic compounds, then back into the atmosphere.
Many industrially important compounds, such as #ammonia
acid, organic nitrates (propellants and explosives), and cyanides, contain nitrogen. The extremely strong triple bond in elemental nitrogen (N≡N), the second strongest bond in any diatomic molecule after carbon monoxide (CO), dominates nitrogen chemistry.
#upsc #chemistry #mpsc #ias