Short answers, pulled from the story.
The discovery of nitrogen is attributed to the Scottish physician Daniel Rutherford, who isolated it in 1772 and called it noxious air. Carl Wilhelm Scheele, Henry Cavendish, and Joseph Priestley studied the same gas at about the same time.
Nitrogen has the chemical symbol N and the atomic number 7. It is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens.
Nitrogen makes up about 78% of Earth's atmosphere, making it the most abundant chemical species in air. At standard temperature and pressure it exists as N2, a colourless and odourless diatomic gas.
Nitrogen gas is held together by a triple bond, N is identical to N, with a dissociation energy of 945.41 kilojoules per mole. It is the second strongest bond in any diatomic molecule after carbon monoxide, which is why dinitrogen is mostly unreactive at room temperature.
Two-thirds of industrially produced nitrogen is sold as gas and one-third as liquid. The gas provides a low-reactivity atmosphere for food packaging, light bulbs, and fire suppression, while liquid nitrogen is a cryogen used for cooling, cryopreservation, and cryotherapy.
Although nitrogen is non-toxic, it can displace oxygen in an enclosed space and cause asphyxiation with few warning symptoms. Two technicians died this way before the first Space Shuttle launch on the 19th of March 1981, and in January 2024 Kenneth Eugene Smith became the first person executed by nitrogen asphyxiation.
Nitrogen occurs in all organisms, primarily in amino acids, proteins, the nucleic acids DNA and RNA, and adenosine triphosphate, and the human body is about 3% nitrogen by mass. Half of global food production now relies on synthetic nitrogen fertilisers made through industrial nitrogen fixation.