Nitrogen (N)


  • Symbol: N
  • Atomic Number: 7
  • Atomic Weight: 14.007
  • Element Classification: Non-metal
  • Discovered By: Daniel Rutherford
  • Discovery Date: 1772
  • Name Origin: Greek: ‘nitron’ and ‘genes’ meaning “native soda” and “forming”
  • Density(g/cc): 0.0012506 (at 0°C, 101.325 kPa)
  • Melting Point: -210.00°C
  • Boiling Point: -195.795°C
  • Appearance: Colorless, odorless gas
  • Atomic Radius(pm): 65


Nitrogen was discovered by Daniel Rutherford in 1772 when he removed oxygen and carbon dioxide from air, revealing a gas that did not support combustion or animal life. This discovery was part of a series of experiments by various scientists who were exploring the components of air. Rutherford called it “noxious air,” but it was later recognized as nitrogen. The name comes from the Greek words ‘nitron’ and ‘genes’, reflecting the element’s presence in nitrates and its role in forming various compounds.

Relation to Other Elements

Nitrogen is a member of the pnictogens group in the periodic table and is characterized by its stable diatomic form (N₂) in the Earth’s atmosphere. This stability is due to the strong triple bond between the nitrogen atoms, making it relatively inert at room temperature. Nitrogen’s ability to form a vast range of compounds comes from its five valence electrons, which allow it to form three covalent bonds. It is essential for all living organisms, being a fundamental component of amino acids, proteins, and nucleic acids. Nitrogen’s reactivity and bonding versatility contrast with the inertness of its molecular form, enabling its vital role in biochemistry and industrial chemistry.

Natural Occurrence

Nitrogen makes up about 78% of the Earth’s atmosphere, making it the largest component. It is essential for life, forming part of the amino acids, proteins, and nucleic acids in all living organisms. Nitrogen is also found in the soil, in the form of nitrates and ammonium salts, which are crucial nutrients for plant growth. It cycles through the environment via the nitrogen cycle, involving processes such as nitrogen fixation, nitrification, denitrification, and ammonification, which transform atmospheric nitrogen into forms usable by living organisms and back.


Nitrogen has various applications, reflecting its importance in different fields:

  • Agriculture: Synthetic fertilizers contain nitrogen compounds, such as ammonium nitrate and urea, critical for plant growth.
  • Industry: Nitrogen gas is used in the production of stainless steel, as a blanketing gas to prevent oxidation, and in the manufacture of electronics.
  • Chemicals: Nitrogen compounds, such as nitric acid and ammonia, are essential for producing a wide range of chemical products, including explosives, plastics, and dyes.
  • Food: Liquid nitrogen is used in food preservation and packaging to displace air and prevent oxidation. It’s also used in the culinary arts for flash-freezing and creating novel textures.
  • Medicine: Nitrogen is used in cryopreservation to store cells, tissues, and other biological samples at very low temperatures.

The discovery of nitrogen was a significant milestone in understanding the composition of the atmosphere and its role in the biosphere and industry. Its abundant natural occurrence and versatile chemical properties make it indispensable in numerous biological, industrial, and environmental processes.

Carbon (C)

Oxygen (O)