Nitrogen (N), Element 7: Facts and Uses

What is nitrogen?

Nitrogen is a gas without colour or smell that makes up about 78 percent of the air. All living things need it to build proteins and DNA.

What is nitrogen used for?

Fertilisers, through ammonia. Liquid nitrogen for freezing food and medical samples. Filling food packets to keep the contents fresh.

Where the name comes from

From the Greek words nitron and genes, meaning 'nitre former'. Nitre is an old name for a potassium salt used in gunpowder.

Key facts

Symbol: N
Atomic number: 7
Atomic mass: 14.007 u
Family: Nonmetal
Period: 2
Group: 15
Block: p
State at room temperature: Gas
Melting point: -210 °C (63.15 K, -346 °F)
Boiling point: -195.8 °C (77.36 K, -320 °F)
Density: 0.0012506 g/cm³ (as a gas at 0 °C)
Electrons per shell: 2, 5
Electron configuration: [He]2s2 2p3
Common oxidation states: +5, +4, +3, +2, +1, -1, -2, -3
Electronegativity (Pauling): 3.04
First ionisation energy: 14.534 eV
Electron affinity: no value
Atomic radius (van der Waals): 155 pm
Discovered: 1772

Place in the periodic table

Nitrogen is element number 7. It sits in period 2 (row 2) of the periodic table, in group 15 (column 15), and belongs to the p-block. Just before it comes carbon (6), and just after it comes oxygen (8). In the same column, phosphorus is below it. Elements in one column tend to behave alike.

Family: Nonmetals.

Physical properties

At room temperature nitrogen is a gas. It melts at -210 °C and boils at -195.8 °C, so it stays liquid over a range of 14 degrees. One litre of the gas weighs about 1.251 grams at 0 °C and normal pressure. That is lighter than air, which weighs about 1.29 grams a litre. It has the 6th lowest melting point of all elements.

Inside the atom

An atom of nitrogen has 7 protons in its nucleus and, when neutral, 7 electrons around it. The electrons are arranged in 2 shells: 2, 5. The outermost shell holds 5 electrons. Written in full, the electron configuration is [He]2s2 2p3.

Its electronegativity on the Pauling scale is 3.04. This number shows how strongly an atom pulls shared electrons towards itself: fluorine, the strongest, is 3.98. Removing one electron from an atom takes 14.534 electronvolts (about 1,402 kilojoules per mole). One mole of nitrogen weighs 14.007 grams, so a single gram contains about 4.30 × 10²² atoms.

The ring picture is a simple model that only counts the electrons in each shell. Real atoms do not look like this.

Next steps

Work out the weight of a compound that contains nitrogen with the molar mass calculator.
Compare it with every other element in the sortable list.
Test yourself with the symbol quiz.

Figures on this page are from PubChem (U.S. National Library of Medicine), as downloaded on 11 November 2026. See About and data sources.