azotu

Azotu, known in chemistry as nitrogen, is a chemical element with the symbol N and atomic number 7. It is the lightest member of the pnictogens and the most abundant component of Earth's atmosphere, making up about 78% by volume. In nature, nitrogen most commonly exists as the diatomic molecule N2, which is very stable due to its strong triple bond.

History and discovery

Nitrogen was identified as a distinct element in 1772 by the Scottish physician and chemist Daniel Rutherford, who described a portion of air that did not support combustion or life as "noxious air." Its elemental nature was later confirmed by other scientists, and nitrogen was recognized as one of the fundamental elements of the atmosphere.

Properties

N2 is a colorless, odorless gas at room temperature and pressure. The nitrogen atom has five valence electrons, but in N2 two atoms share three pairs of electrons, forming a very strong bond. This makes N2 relatively inert and chemically unreactive under standard conditions, though it can form compounds under appropriate catalysts and extreme conditions. Nitrogen can exist in various oxidation states in compounds, such as in ammonia (NH3), nitrates (NO3−), and nitrites (NO2−). Its boiling point is −196 °C, making liquid nitrogen a common cryogenic fluid.

Occurrence and biological role

Nitrogen is essential for all living organisms, as it is a key component of amino acids, nucleic acids, and many biomolecules. It cycles through the environment via fixation ( converting atmospheric N2 into reactive forms ), nitrification, assimilation, and denitrification, driven by bacteria and other microorganisms.

Production and uses

Industrial nitrogen is produced mainly by fractional distillation of liquid air or air separation methods. The Haber-Bosch process synthesizes ammonia (NH3) from nitrogen and hydrogen, a cornerstone for fertilizer production and modern agriculture. Other uses include inert atmospheres in metallurgy and food packaging, and the production of various nitrogen-containing chemicals.

Safety

Nitrogen gas is non-toxic but can act as an asphyxiant in enclosed spaces by displacing oxygen. Proper ventilation is essential in environments with high nitrogen concentrations.