nitrógen

Nitrogen is a chemical element with the symbol N and atomic number 7. It is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. Under standard conditions, nitrogen is a diatomic, colorless, odorless, tasteless, and nearly inert gas that constitutes 78.08% by volume of Earth's atmosphere. It is the most abundant element in Earth's biosphere, primarily due to its presence in the atmosphere and its essential role in organic compounds.

Nitrogen was first identified as an element in 1772 by Scottish physician Daniel Rutherford, who described it as a gas that was neither carbon dioxide nor oxygen. Later, in 1776, French chemist Antoine Lavoisier named it *azote*, from the Greek *azotos*, meaning "without life," because it does not support combustion. The modern name "nitrogen" derives from the Latin *nitrogenium*, coined by Swedish chemist Carl Wilhelm Scheele, reflecting its presence in nitrates and nitrites.

Nitrogen is a key component of amino acids, nucleic acids (DNA and RNA), and proteins, making it essential for life. It is found in all living organisms, primarily in the form of organic compounds. In the atmosphere, nitrogen is relatively inert due to the strong triple bond between its two atoms (N≡N), which requires high temperatures or specific catalysts to break. This property is exploited in the Haber-Bosch process, an industrial method for synthesizing ammonia (NH₃) from nitrogen and hydrogen, which is critical for fertilizer production and food security.

Nitrogen is also used in various industrial applications, including as an inert atmosphere for preventing oxidation in manufacturing processes, as a refrigerant, and in the production of explosives and plastics. In its oxidized forms, such as nitric acid (HNO₃) and nitrates, nitrogen plays a role in environmental processes, including acid rain and eutrophication of water bodies. Despite its abundance, elemental nitrogen is not directly usable by most organisms, which rely on nitrogen-fixing bacteria to convert it into usable forms like ammonia.