What is the atomic number of nitrogen?

Nitrogen has atomic number 7, meaning its nucleus contains exactly seven protons. It is the seventh element on the periodic table, a member of Group 15 (pnictogens) in Period 2.

What are the stable isotopes of nitrogen?

Nitrogen has two stable isotopes: nitrogen-14 (¹⁴N) with a natural abundance of about 99.636%, and nitrogen-15 (¹⁵N) with about 0.364% abundance. ¹⁵N is widely used in stable isotope labeling for NMR spectroscopy and metabolic tracing.

What is the electron configuration of nitrogen?

Nitrogen has the electron configuration 1s² 2s² 2p³ (or [He] 2s² 2p³ in noble gas notation). Its half-filled 2p subshell (three unpaired electrons obeying Hund's rule) gives nitrogen unusual stability and accounts for the remarkable strength of the N≡N triple bond.

Why is nitrogen gas (N₂) so unreactive?

Molecular nitrogen (N₂) has a triple bond with a bond dissociation energy of 945 kJ/mol, one of the strongest bonds in chemistry. This makes N₂ extremely inert under ordinary conditions. Only at high temperatures and pressures (Haber process) or via biological nitrogen fixation can N₂ be converted into reactive nitrogen compounds.

What is liquid nitrogen used for?

Liquid nitrogen (LN₂) boils at −195.79 °C (77.36 K) at atmospheric pressure and is used as a cryogenic coolant for preserving biological samples, rapid food freezing, cooling superconducting magnets, shrink-fitting metal parts, dermatological treatment, and cryogenic grinding of materials that are difficult to process at room temperature.

Why is nitrogen essential for life?

Nitrogen is a key component of amino acids (the building blocks of proteins), nucleotides (the building blocks of DNA and RNA), chlorophyll, and many other biomolecules. Despite its abundance in the atmosphere, most organisms cannot use N₂ directly — they depend on nitrogen fixation by specialized bacteria or industrial fertilizer production.

What are 10 key properties of nitrogen?

(1) Atomic number 7, (2) symbol N, (3) atomic mass 14.007 u, (4) electron configuration [He] 2s² 2p³, (5) Group 15 pnictogen, (6) Period 2, (7) diatomic gas (N₂), (8) colorless and odorless, (9) boiling point −195.79 °C, (10) melting point −210 °C.

Nitrogen Element Properties

Name: Nitrogen Element Properties
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Author: Nham Vu

Complete reference for Nitrogen (N, element 7): atomic data, electron configuration with interactive shell diagram, isotopes, physical constants, and a temperature unit toggle.

7 N 14.007

Nitrogen

Nonmetal — Period 2, Group 15

Atomic Identity

Atomic Number

Symbol

Standard Atomic Wt.

14.007 u

IUPAC 2021

Period

Group

15 (Pnictogens)

Block

p-block

Electron Configuration

Full notation 1s² 2s² 2p³

Noble gas shorthand [He] 2s² 2p³

Electrons per shell 2, 5

Valence electrons 5

Unpaired electrons 3

Spin multiplicity 4 (quartet)

Orbital Diagram

7 electrons — 3 unpaired in 2p (Hund's rule)

Paramagnetic

Half-filled 2p subshell — quartet ground state (⁴S°₃/₂)

Physical Properties

State at STP Gas (colorless)

Density (gas, STP) 1.2506 g/L

Melting Point -210.01 °C

Boiling Point -195.79 °C

Critical Temperature -146.96 °C (126.19 K)

Critical Pressure 3.39 MPa

Heat of Vaporization 5.57 kJ/mol

Heat of Fusion 0.72 kJ/mol

Molar Heat Capacity 29.124 J/(mol·K)

Thermal Conductivity 25.83 mW/(m·K)

Crystal Structure (solid) Hexagonal

Color Colorless

Isotopes of Nitrogen

Isotope	Symbol	Protons	Neutrons	Mass (u)	Natural Abundance	Stability
Nitrogen-13	¹³N	7	6	13.00574	Radioactive	Unstable β⁺ decay, t½ = 9.965 min
Nitrogen-14	¹⁴N	7	7	14.00307	99.636%	Stable
Nitrogen-15	¹⁵N	7	8	15.00011	0.364%	Stable
Nitrogen-16	¹⁶N	7	9	16.00610	Radioactive	Unstable β⁻ decay, t½ = 7.13 s
Nitrogen-17	¹⁷N	7	10	17.00845	Radioactive	Unstable β⁻ decay, t½ = 4.173 s

Nitrogen-15 (¹⁵N) is a stable heavy isotope extensively used in NMR spectroscopy (¹⁵N-NMR) and as a metabolic tracer in biological research. It is also used in stable isotope dilution analysis for precise quantification.

Chemical Properties

Electronegativity (Pauling) 3.04

Electron Affinity -7 kJ/mol (unfavorable)

1st Ionization Energy 1402.3 kJ/mol

2nd Ionization Energy 2856.0 kJ/mol

3rd Ionization Energy 4578.1 kJ/mol

Oxidation States -3, -2, -1, 0, +1, +2, +3, +4, +5

Common oxidation state -3 (amines, ammonia)

N≡N Bond Energy 945 kJ/mol

Magnetic Ordering Diamagnetic (N₂ molecule)

Atomic Properties

Covalent Radius 71 pm

Van der Waals Radius 155 pm

Ionic Radius (N³⁻) 146 pm

Atomic Radius (empirical) 65 pm

N–N single bond length 145 pm

N=N double bond length 125 pm

N≡N triple bond length 109.76 pm

Ground State Term Symbol ⁴S°₃/₂

Number of Energy Levels 2

Key Facts About Nitrogen

Atmospheric Abundance

Nitrogen gas (N₂) constitutes about 78.09% of Earth's dry atmosphere by volume, making it by far the most abundant gas. It is produced by volcanic outgassing and biological denitrification over geological timescales.

Essential for Life

Nitrogen is a core element in all amino acids, proteins, DNA, RNA, ATP, and chlorophyll. Despite its atmospheric abundance, living organisms cannot use N₂ directly — they rely on nitrogen fixation by bacteria (e.g., Rhizobium) or industrial Haber-Bosch synthesis.

Haber-Bosch Process

The Haber-Bosch process converts atmospheric N₂ into ammonia (NH₃) at high temperatures (~400–500 °C) and pressures (~150–300 atm) using an iron catalyst. It underpins modern agriculture — roughly half the nitrogen in the human body comes from industrially fixed nitrogen.

Liquid Nitrogen Cryogenics

Liquid nitrogen (LN₂) is an inexpensive cryogenic fluid produced by fractional distillation of air. It is used for preserving biological specimens, rapid food freezing, cooling MRI and NMR superconducting magnets, skin lesion removal, and cryogenic hardening of metals.

Nitrogen in Explosives

Many high-energy materials exploit nitrogen chemistry: nitroglycerin (C₃H₅N₃O₉), TNT (C₇H₅N₃O₆), RDX, and ANFO (ammonium nitrate + fuel oil) all derive their energy from the formation of the extremely stable N₂ molecule from higher-energy N–O and N–C bonds.

Inert Atmosphere Applications

Because N₂ is cheap, abundant, and non-reactive under normal conditions, it is widely used to create inert atmospheres in food packaging (MAP), electronics manufacturing, metal heat treatment, and pharmaceutical storage to prevent oxidation, combustion, or moisture ingress.

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Summary

Complete reference for Nitrogen (N, element 7): atomic data, electron configuration with interactive shell diagram, isotopes, physical constants, and a temperature unit toggle.

How it works

Browse the atomic identity section for symbol, atomic number, and standard atomic weight.
Check the electron configuration panel for orbital notation and the interactive shell diagram.
Toggle the temperature unit (°C / °F / K) on the physical properties card to convert melting and boiling points.
Review the isotopes table for nitrogen-14 and nitrogen-15 data including natural abundance.
Consult the chemical properties panel for electronegativity, ionization energies, and oxidation states.
Explore the key facts section for biological roles, industrial applications, and atmospheric significance.

Use cases

Look up nitrogen constants for chemistry homework or exams.
Verify atomic data when writing lab reports or research papers.
Reference isotope data for stable isotope labeling or mass spectrometry.
Check physical properties for engineering applications involving cryogenic nitrogen.
Teach or learn nitrogen chemistry and its essential role in biology.
Confirm electron configuration before writing molecular orbital diagrams.
Quick-reference oxidation states for inorganic or analytical chemistry.
Review electronegativity and ionization energy for spectroscopy or computational chemistry.

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Last updated: 2026-05-28 · Reviewed by Nham Vu