Nitrogen (N)
Reactive nonmetal
Nitrogen makes up about 78% of the air you are breathing right now, yet the N₂ molecule is so stable that most organisms cannot use it directly. “Fixing” nitrogen into usable compounds feeds the world through fertilisers.
Position on the periodic table
Atomic properties
| Atomic number | 7 |
|---|---|
| Atomic mass | 14.007 amu |
| Electron configuration | 1s2 2s2 2p3 |
| Noble gas shorthand | [He] 2s2 2p3 |
| Electrons per shell | 2, 5 |
| Valence electrons (outer shell) | 5 |
| Common oxidation states | -3, +3, +5 |
| Electronegativity (Pauling) | 3.04 |
| Covalent radius (approx.) | 71 pm |
| First ionization energy | 1402 kJ/mol |
| Electron affinity | -6.8 kJ/mol |
Physical properties
| State at 25 °C | Gas |
|---|---|
| Density | 1.251 g/L |
| Melting point | -210 °C (63.15 K) |
| Boiling point | -195.79 °C (77.36 K) |
| Appearance | colorless gas, liquid or solid |
| Radioactive | No |
| Origin | Occurs naturally |
Electron configuration of nitrogen
Nitrogen's ground-state electron configuration is 1s2 2s2 2p3, usually shortened to [He] 2s2 2p3. Its electrons occupy 2 shells (2, 5), placing it in period 2 of the p-block. The 5 outer-shell electrons drive its bonding behaviour. Explore it interactively in the electron configuration calculator.
Uses of nitrogen
- Ammonia production for fertilisers
- Inert atmosphere for food packaging and electronics
- Liquid nitrogen for freezing and cryogenics
- Explosives and propellants (as nitrates)
Biological role: Essential — found in every amino acid, protein and DNA base.
Occurrence: 78% of the atmosphere by volume; also in nitrate minerals and all living things.
Common compounds of nitrogen
NH3
Ammonia
HNO3
Nitric acid
N2O
Nitrous oxide
KNO3
Potassium nitrate
History and discovery
Discovered: 1772 — Daniel Rutherford. Name origin: From Greek nitron + genes — “nitre former” (nitre is potassium nitrate).
Daniel Rutherford described “noxious air” left after removing oxygen from air in 1772.
Safety notes
Nitrogen gas is not toxic but can displace oxygen in enclosed spaces. Liquid nitrogen causes instant frostbite.
Educational context only — always follow your school's laboratory rules and never handle chemicals without proper supervision. See our disclaimer.
Practice questions
Quick practice: Nitrogen
1. What is the chemical symbol of Nitrogen?
2. What is the atomic number of Nitrogen?
3. Which category does Nitrogen belong to?
4. What is the state of Nitrogen at room temperature?
5. Which period of the periodic table is Nitrogen in?
Nitrogen FAQs
What is the atomic number of nitrogen?
Nitrogen's atomic number is 7 — every nitrogen atom has 7 protons in its nucleus.
What is the symbol for nitrogen?
N. From Greek nitron + genes — “nitre former” (nitre is potassium nitrate).
Is nitrogen a metal, nonmetal, or metalloid?
Nitrogen is classified as a reactive nonmetal.
What state is nitrogen at room temperature?
At about 25 °C, nitrogen is a gas. It melts at -210 °C.
How many valence electrons does nitrogen have?
Nitrogen has 5 electrons in its outer shell (shell pattern: 2, 5).
What is nitrogen used for?
Key uses include: ammonia production for fertilisers; inert atmosphere for food packaging and electronics; liquid nitrogen for freezing and cryogenics.
Related elements
Keep working with this element
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