The chemical symbol for nitrogen is "N." Nitrogen is a non-metallic element with the atomic number 7 and is essential for life on Earth. It makes up about 78% of the Earth's atmosphere and is a critical component of amino acids and nucleic acids, which are necessary for the growth and reproduction of all living organisms. Nitrogen is found in various compounds and is used in fertilizers to promote plant growth. It exists naturally in the atmosphere as a diatomic molecule (N2) and plays a vital role in the nitrogen cycle, essential for ecological balance.