007Reactive nonmetal · Group 15 · Period 2

Nitrogen

Nitrogen (N) is element 7, a reactive nonmetal in the p-block — group 15, period 2. It is a gas at room temperature with 2 electron shells (2, 5) and an atomic mass of 14.007 u.

Atomic mass: 14.01 u
Phase · STP: gas
Melting: 63 K · -210 °C
Boiling: 77 K · -196 °C
Electronegativity: 3.04
Density: 1.251 g/cm³

Photograph — Jurii, CC BY 3.0 <https://creativecommons.org/licenses/by/3.0>, via Wikimedia Commons, source: https://images-of-elements.com/nitrogen.php

Emission spectrum

The visible light Nitrogen emits when energised — its unique spectral fingerprint.

Identity

Atomic number: 7
Standard atomic weight: 14.01 u
Category: Reactive nonmetal
Group: 15 · Pnictogens
Period: 2
Block: p-block
Oxidation states: +5, +4, +3, +2, +1, -1, -2, -3

Physical properties

Melting point: 63 K · -210 °C
Boiling point: 77 K · -196 °C
Density: 1.251 g/cm³
Molar heat capacity: —
Atomic radius: 155 pm
Electron affinity: -6.8 kJ/mol

Atomic structure

7protons

7neutrons

7electrons

5valence e⁻

Noble-gas notation: [He] 2s2 2p3
Full configuration: 1s2 2s2 2p3
Electrons per shell: 2, 5

Periodic trends

Where Nitrogen ranks across all 118 elements.

Electronegativity3.04

Ionization energy1402.3 kJ/mol

Electron affinity-6.8 kJ/mol

Density1.251 g/cm³

Atomic radius155 pm

Ionization energies

Energy to remove each successive electron (kJ/mol).

1.4k

2.9k

4.6k

7.5k

9.4k

53.3k

64.4k

Successive ionization energies (kJ/mol, log scale).

Discovery

Discovered: 1772
Discovered by: Daniel Rutherford
Named by: Jean-Antoine Chaptal
Appearance: colorless gas, liquid or solid