Nitrogen is a chemical element with symbol N and atomic number 7. It is an odorless, tasteless, colorless nonmetallic chemical element which appears in great abundance (78.09% ) in the Earth’s atmosphere. Nitrogen was discovered by Scottish physician Daniel Rutherford, in 1772.
Approximately 4/5 of the Earth’s atmosphere is made up of nitrogen and the element is the seventh most abundant in the universe. Its occurrence there is thought to be entirely due to synthesis by fusion from carbon and hydrogen in supernovas. Due to the volatility of elemental nitrogen and its common compounds with hydrogen and oxygen, nitrogen is far less common on the rocky planets of the inner Solar System. However, as is the case on Earth, nitrogen and its compounds occur commonly as gases in the atmospheres of planets and moons that have atmospheres.
Some of the most important compounds, like ammonia, organic nitrates, nitric acid etc. contain nitrogen. The very strong bond in elemental nitrogen dominates nitrogen chemistry, causing difficulty for both organisms and industry in breaking the bond to convert the N2 into useful compounds.
Nitrogen is found in all the living organisms, but mostly in amino acids. It is also the fourth most abundent element (3%) after oxygen, carbon and hydrogen, in human body. Nitrogen resides in the chemical structure of almost all neurotransmitters, representing a defining component of alkaloids, biological molecules produced as secondary metabolites by many organisms. Regarding the cycle of nitrogen, the element moves from the air into the biosphere and organic compounds, then back into the atmosphere. Synthetically produced nitrates are key ingredients of industrial fertilizers and key pollutants in causing the eutrophication of water systems.