Quick answerNitrogen (N) is a nonmetal with atomic number 7 and an atomic mass of 14.007 (2023), in group 15, period 2. It was discovered by Daniel Rutherford in 1772. It is used for ammonia fertiliser production and food freezing and packaging. Its electron configuration is [He] 2s2 2p3.
Nitrogen makes up 78% of the air you breathe, yet in that form it is almost completely inert, plants and animals cannot use it directly. Its real value comes when it is fixed into ammonia fertiliser, which feeds roughly half the world's population, and into explosives, dyes, and medicines. Liquid nitrogen's deep cold also freezes food, preserves cells, and shrinks metal parts for fitting.
Key facts
| Symbol | N |
|---|---|
| Atomic number | 7 |
| Atomic mass | 14.007 (IUPAC standard atomic weight, 2023) |
| Category | nonmetal |
| Group | 15 |
| Period | 2 |
| Block | p-block |
| Electron configuration | [He] 2s2 2p3 |
| Discovered | Daniel Rutherford, 1772 |
| Uses | ammonia fertiliser production, food freezing and packaging, liquid nitrogen cryopreservation, explosives manufacturing, electronics manufacturing |
Overview
Nitrogen is the gas that fills most of the air around you: about 78% of the atmosphere is nitrogen, yet in that form it is almost completely inert. It has atomic number 7, an atomic mass of 14.007, and the electron configuration [He] 2s2 2p3, and it sits in group 15, period 2 of the periodic table. Daniel Rutherford isolated it in 1772 and called it noxious air, because a candle would not burn in it and a mouse could not live in it. Nitrogen's double life is the point: as a gas it does almost nothing, but once its atoms are fixed into compounds it becomes essential. Plants and animals cannot use nitrogen gas directly, so fertiliser makers combine nitrogen with hydrogen to make ammonia, and ammonia fertiliser now feeds roughly half the world's population. The same chemistry feeds explosives, dyes and medicines. Liquid nitrogen, cold enough to freeze flesh on contact, freezes food, preserves cells and tissue, and shrinks metal parts so they can be fitted together. Nitrogen gas also protects food in sealed packets, keeps electronic parts free of oxygen during manufacture, and fills aircraft tyres. Lightning and soil bacteria fix a little nitrogen naturally, but industry now fixes far more than nature does.
Frequently asked questions
What is nitrogen used for?
Nitrogen is mainly used to make ammonia fertiliser, which feeds roughly half the world's population, and to make explosives, dyes and medicines. Liquid nitrogen freezes food, preserves cells and shrinks metal parts for fitting. Nitrogen gas also protects packaged food, fills aircraft tyres and shields electronics during manufacture.
What is the symbol for nitrogen?
The chemical symbol for nitrogen is N, from its name, which comes from the Greek for nitre-former. It has atomic number 7 and a standard atomic mass of 14.007, and it sits in group 15 and period 2 of the periodic table. Daniel Rutherford isolated it in 1772, and it makes up about 78% of the air.
What is the atomic number of nitrogen?
Nitrogen has atomic number 7, so it is the seventh element in the periodic table. Its atom holds seven protons and seven electrons, and its standard atomic mass is 14.007. It is a nonmetal in group 15 and period 2, with the electron configuration [He] 2s2 2p3, and it makes up about 78% of the air you breathe.
Is nitrogen a gas?
Yes, nitrogen is a gas at room temperature. It is colourless and odourless, and it makes up about 78% of the air. Nitrogen gas is very unreactive, which is why it is used to protect food and electronics from oxygen. Cooled far below freezing it becomes a liquid, used to freeze food and preserve cells.
Why is nitrogen important for plants?
Plants need nitrogen to build proteins, DNA and chlorophyll, the green pigment that captures sunlight, but they cannot use nitrogen gas from the air directly. They take it up as compounds from the soil, which is why farmers add nitrogen fertiliser. Soil bacteria and lightning fix a little nitrogen naturally, but far less than crops need.
Quick quiz
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Keep exploring
- Periodic table — all 118 elements
- Hydrogen (H) — another nonmetal, atomic number 1
- Carbon (C) — another nonmetal, atomic number 6
- Oxygen (O) — another nonmetal, atomic number 8
- Phosphorus (P) — another nonmetal, atomic number 15
- Sulfur (S) — another nonmetal, atomic number 16
- Selenium (Se) — another nonmetal, atomic number 34
Sources & last updated
- CIAAW — Standard Atomic Weights
- PubChem Periodic Table
- Wikipedia — Timeline of chemical element discoveries
Last updated: . Figures are shown with their year; where sources disagree, the value is left out rather than estimated.