Nitrogen is a chemical element with symbol N and atomic number 7. It is the lightest pnictogen and at room temperature, it is a transparent, odorless diatomic gas. Nitrogen is a common element in the universe, estimated at about seventh in total abundance in the Milky Way and the Solar System.
Three reasons Nitrogen stands out
- 1
Makes up most of Earth's atmosphere.
- 2
In liquid form it boils at −196 °C and is used to instantly freeze biological samples.
- 3
It is an essential building block of amino acids, proteins, and DNA in all living things.
Breaking the strongest everyday bond
Pairs of nitrogen atoms fill most of the atmosphere, held together by a stubborn triple bond. Life cannot use that reservoir directly, so microbes, lightning, and industry must “fix” nitrogen into reactive compounds. Those compounds feed crops, build proteins, and can also become powerful explosives.