Nitrogen is a chemical element with the symbol N and atomic number 7. It is a nonmetal and the lightest member of group 15 (the pnictogens) on the periodic table

. At standard temperature and pressure, nitrogen exists as a colorless, odorless, and tasteless diatomic gas (N₂), which makes up about 78% of Earth's atmosphere by volume, making it the most abundant gas in the air we breathe

. Nitrogen is essential for life, as it is a fundamental component of amino acids (the building blocks of proteins), nucleic acids (DNA and RNA), and other biological molecules like ATP, which is vital for energy transfer in cells

. The nitrogen cycle describes how nitrogen moves through the atmosphere, soil, water, plants, animals, and bacteria, changing forms to be usable by living organisms

. Industrially, nitrogen is produced mainly by separating it from air and is used as an inert gas in food packaging, electronics manufacturing, and steel annealing. Liquid nitrogen, which is extremely cold, is used for cryogenic applications such as rapid freezing of food and biological samples

. Nitrogen compounds like ammonia and nitrates are important fertilizers but can also cause environmental issues like water eutrophication if misused

. In summary, nitrogen is a vital, abundant, inert gas essential for life and widely used in industry due to its chemical stability and role in biological systems