Na 11

Sodium (Na)

alkali-metal

Period: 3 Group: 1 Block: s

Solid

Standard Atomic Weight

Electron configuration

[Ne] 3s¹

Melting point

97.8 °C (370.95 K)

Boiling point

882.85 °C (1156 K)

Density

970 kg/m³

Oxidation states

−1, 0, +1

Electronegativity (Pauling)

0.93

Ionization energy (1st)

Discovery year

1807

Atomic radius

180 pm

Details

Name origin Medieval Latin: sodanum, (headache remedy); symbol from Latin natrium, (sodium carbonate).

Discovery country England

Discoverers Sir Humphrey Davy

Sodium is a soft, highly reactive alkali metal in group 1. It has one valence electron and almost always forms Na⁺ in ordinary compounds. The element is abundant in seawater, evaporite deposits, and silicate minerals, but it is never found free in nature because it reacts readily with water, oxygen, and many nonmetals. Its salts are central to physiology, glassmaking, detergents, and bulk chemical manufacture.

Sodium, like every reactive element, is never found free in nature. Sodium is a soft, bright, silvery metal which floats on water. Decomposition in water results in the evolution of hydrogen and the formation of the hydroxide. It may or may not ignite spontaneously on water, depending on the amount of oxide and metal exposed to the water. It normally does not ignite in air at temperatures below 115°C.

The name derives from the English soda and Latin sodanum for "headache remedy". The symbol Na derives from the Latin natrium for "natron" (soda in English). Sodium was discovered in 1807 by the English chemist Humphry Davy from electrolysis of caustic soda (NaOH).

Although sodium is the sixth most abundant element on earth and comprises about 2.6% of the earth's crust, it is a very reactive element and is never found free in nature. Pure sodium was first isolated by Sir Humphry Davy in 1807 through the electrolysis of caustic soda (NaOH). Since sodium can ignite on contact with water, it must be stored in a moisture free environment.

From the English word, soda; Medieval Latin, sodanum: a headache remedy. Long recognized in compounds, sodium was first isolated by Davy in 1807 by electrolysis of caustic soda.

Read about Sodium on Wikipedia

Images

Properties

Physical

Atomic radius (empirical) 180 pm

Covalent radius 166 pm

Van der Waals radius 227 pm

Metallic radius 157 pm

Density

Molar volume 0.0237 L/mol

Phase at STP solid

Melting point 97.8 °C

Boiling point 882.85 °C

Thermal conductivity 142 W/(m·K)

Specific heat capacity 1.228 J/(g·K)

Molar heat capacity 28.23 J/(mol·K)

Crystal structure bcc

Chemical

Electronegativity (Pauling) 0.93

Electronegativity (Allen) 0.869

Electron affinity

Ionization energy (1st)

Ionization energy (2nd)

Ionization energy (3rd)

Ionization energy (4th)

Ionization energy (5th)

Oxidation states −1, 0, +1

Valence electrons 1

Electron configuration

Electron configuration (semantic)

Thermodynamic

Critical point (temperature) 2300 °C

Critical point (pressure) 3.500000e+7 Pa

Heat of fusion 0.02694719 eV

Heat of vaporization 1.012593 eV

Heat of sublimation 1.11209 eV

Heat of atomization 1.11209 eV

Atomization enthalpy

Nuclear

Stable isotopes 1

Discovery year 1807

Abundance

Abundance (Earth's crust) 2.360e+4 mg/kg

Abundance (ocean)

Reactivity

N/A

Crystal Structure

Lattice constant a 423 pm

Electronic Structure

Electrons per shell 2, 8, 1

Identifiers

CAS number 7440-23-5

Term symbol

InChI InChI=1S/Na

InChI Key KEAYESYHFKHZAL-UHFFFAOYSA-N

Electron Configuration Measured

Ion charge

Protons 11

Electrons 11

Charge Neutral

Configuration Na: 3s¹

[Ne] 3s¹

1s² 2s² 2p⁶ 3s¹

Orbital diagram

↑↓

2/2

↑↓

2/2

↑↓

6/6

↑

1/2 1↑

Total electrons: 11 Unpaired: 1

Atomic model

Protons 11

Neutrons 12

Electrons 11

Mass number 23

Stability Stable

Isotopes change neutron count, mass, and stability — not the electron configuration of a neutral atom.

Schematic atomic model, not to scale.

Atomic Fingerprint

Emission / Absorption Spectrum

Emission Visible: 380–750 nm

Isotope Distribution

Mass number	Atomic mass (u)	Natural abundance	Half-life
23 Stable	22.989769282 ± 0.0000000019	100.0000%	Stable

Measured

Phase / State

Solid 25 °C (298.15 K)

Reason: 72.8 °C below melting point (97.8 °C)

Melting point 97.8 °C

Boiling point 882.85 °C

Below melting by 72.8 °C

0 K Current temperature: 25 °C 6000 K

Phase timeline

Schematic, not to scale

Solid

Liquid

Gas

Melting

Boiling

25°C

Solid

Liquid

Gas

Current

Phase transition points

Melting point Literature

97.8 °C

Boiling point Literature

882.85 °C

Current phase Calculated
Solid

Transition energies

Heat of fusion Literature

0.02694719 eV

Energy required to melt 1 mol at melting point

Heat of vaporization Literature

1.012593 eV

Energy required to vaporize 1 mol at boiling point

Heat of sublimation Literature

1.11209 eV

Energy required to sublime 1 mol at sublimation point

Density

Reference density Literature

970 kg/m³

At standard conditions

Current density Calculated

970 kg/m³

At standard conditions

Advanced

Critical point Literature

2300 °C

Atomic Spectra

Showing 10 of 11 Atomic Spectra. Sorted by ion charge (ascending).

Lines Holdings ?

Ion	Charge	Total lines	Transition probabilities	Level designations
Na I	0	869	523	858
Na II	+1	1345	176	605
Na III	+2	560	417	560
Na IV	+3	687	671	687
Na V	+4	529	503	527
Na VI	+5	657	594	641
Na VII	+6	1374	1369	1374
Na VIII	+7	464	456	464
Na IX	+8	172	138	172
Na X	+9	594	586	594

NIST Lines Holdings →

Levels Holdings ?

Ion	Charge	Levels
Na I	0	430
Na II	+1	165
Na III	+2	120
Na IV	+3	104
Na V	+4	102
Na VI	+5	116
Na VII	+6	142
Na VIII	+7	89
Na IX	+8	46
Na X	+9	111

NIST Levels Holdings →

11 Na 22.98976928

Sodium — Atomic Orbital Visualizer

[Ne]3s1

Energy levels 2 8 1

Oxidation states -1, 0, +1

HOMO 3s n=3 · l=0 · m=0

Sodium — Atomic Orbital Visualizer Preview

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11 Na 22.98976928

Sodium — Crystal Structure Visualizer

Body-Centered Cubic · Pearson cI2

Experimental

Pearson cI2

Coord. № 8

Packing 68.000%

Sodium — Crystal Structure Visualizer Preview

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Ionic Radii

Charge	Coordination	Spin	Radius
+1	4	N/A	99 pm
+1	5	N/A	100 pm
+1	6	N/A	102 pm
+1	7	N/A	112.00000000000001 pm
+1	8	N/A	118 pm
+1	9	N/A	124 pm
+1	12	N/A	139 pm

Compounds

22.990 u

Na+

22.990 u

21.994 u

23.991 u

22.990 u

Na+

23.991 u

Na+

21.994 u

Na+

22.990 u

Isotopes (1)

Thirteen isotopes of sodium are recognized.

	Mass number	Atomic mass (u)	Natural abundance	Half-life	Decay mode
	23 Stable	22.989769282 ± 0.0000000019	100.0000%	Stable	stable

23 Stable

Atomic mass (u) 22.989769282 ± 0.0000000019

Natural abundance 100.0000%

Half-life Stable

Decay mode

stable

Spectral Lines

Showing 50 of 480 Spectral Lines. Only spectral lines with measured intensity are shown by default.

Wavelength (nm)	Intensity	Ion stage	Type	Transition	Accuracy	Source
588.995094 nm	80000	Na I	emission	2p6.3s 2S → 2p6.3p 2P*	Measured	NIST
589.592424 nm	40000	Na I	emission	2p6.3s 2S → 2p6.3p 2P*	Measured	NIST
388.181 nm	420	Na I	emission	2p5.(2P).3s.3p.(3P) 4D → 2p5.3s.(3P).3d 4F	Measured	NIST
443.234 nm	310	Na I	emission	2p5.(2P).3s.3p.(3P) 4S → 2p5.3s.(3P).4s 4P	Measured	NIST
411.3703 nm	300	Na II	emission	2s2.2p5.3p 1S → 2s2.2p5.(2P<1/2>).3d 2[3/2]	Measured	NIST
507.12 nm	270	Na I	emission	2p5.(2P).3s.3p.(3P) 4D → 2p5.3s.(3P).4s 4P	Measured	NIST
412.3069 nm	250	Na II	emission	2s2.2p5.3p 1S → 2s2.2p5.(2P<1/2>).4s 2[1/2]	Measured	NIST
423.335 nm	250	Na II	emission	2s2.2p5.(2P<3/2>).3d 2[5/2] → 2s2.2p5.(2P*<1/2>).4f 2[7/2]	Measured	NIST
424.09 nm	250	Na II	emission	2s2.2p5.(2P<3/2>).3d 2[5/2] → 2s2.2p5.(2P*<1/2>).4f 2[7/2]	Measured	NIST
429.249 nm	250	Na II	emission	2s2.2p5.(2P<3/2>).3d 2[1/2] → 2s2.2p5.(2P*<3/2>).4f 2[5/2]	Measured	NIST
429.287 nm	250	Na II	emission	2s2.2p5.(2P<3/2>).3d 2[1/2] → 2s2.2p5.(2P*<3/2>).4f 2[3/2]	Measured	NIST
430.882 nm	250	Na II	emission	2s2.2p5.(2P<3/2>).3d 2[1/2] → 2s2.2p5.(2P*<3/2>).4f 2[3/2]	Measured	NIST
430.904 nm	250	Na II	emission	2s2.2p5.(2P<3/2>).3d 2[1/2] → 2s2.2p5.(2P*<3/2>).4f 2[3/2]	Measured	NIST
432.091 nm	250	Na II	emission	2s2.2p5.(2P<3/2>).3d 2[3/2] → 2s2.2p5.(2P*<3/2>).4f 2[5/2]	Measured	NIST
433.729 nm	250	Na II	emission	2s2.2p5.(2P<3/2>).3d 2[3/2] → 2s2.2p5.(2P*<3/2>).4f 2[3/2]	Measured	NIST
434.412 nm	250	Na II	emission	2s2.2p5.3p 1S → 2s2.2p5.(2P<3/2>).4s 2[3/2]	Measured	NIST
439.281 nm	250	Na II	emission	2s2.2p5.(2P<3/2>).3d 2[7/2] → 2s2.2p5.(2P*<3/2>).4f 2[9/2]	Measured	NIST
408.1372 nm	200	Na II	emission	2s2.2p5.(2P<3/2>).3d 2[3/2] → 2s2.2p5.(2P*<1/2>).4f 2[5/2]	Measured	NIST
436.859 nm	200	Na II	emission	2s2.2p5.3p 1S → 2s2.2p5.(2P<3/2>).3d 2[3/2]	Measured	NIST
437.522 nm	200	Na II	emission	2s2.2p5.(2P<3/2>).3d 2[7/2] → 2s2.2p5.(2P*<3/2>).4f 2[7/2]	Measured	NIST
438.748 nm	200	Na II	emission	2s2.2p5.(2P<3/2>).3d 2[7/2] → 2s2.2p5.(2P*<3/2>).4f 2[7/2]	Measured	NIST
440.512 nm	200	Na II	emission	2s2.2p5.(2P<3/2>).3d 2[7/2] → 2s2.2p5.(2P*<3/2>).4f 2[9/2]	Measured	NIST
444.669 nm	200	Na II	emission	2s2.2p5.(2P<1/2>).3d 2[5/2] → 2s2.2p5.(2P*<1/2>).4f 2[5/2]	Measured	NIST
444.741 nm	200	Na II	emission	2s2.2p5.(2P<1/2>).3d 2[5/2] → 2s2.2p5.(2P*<1/2>).4f 2[7/2]	Measured	NIST
445.473 nm	200	Na II	emission	2s2.2p5.(2P<1/2>).3d 2[5/2] → 2s2.2p5.(2P*<1/2>).4f 2[5/2]	Measured	NIST
445.523 nm	200	Na II	emission	2s2.2p5.(2P<1/2>).3d 2[5/2] → 2s2.2p5.(2P*<1/2>).4f 2[7/2]	Measured	NIST
445.72 nm	200	Na II	emission	2s2.2p5.(2P<3/2>).4s 2[3/2] → 2s2.2p5.(2P*<3/2>).4f 2[5/2]	Measured	NIST
447.463 nm	200	Na II	emission	2s2.2p5.(2P<3/2>).4s 2[3/2] → 2s2.2p5.(2P*<3/2>).4f 2[3/2]	Measured	NIST
447.88 nm	200	Na II	emission	2s2.2p5.(2P<1/2>).3d 2[3/2] → 2s2.2p5.(2P*<1/2>).4f 2[5/2]	Measured	NIST
448.167 nm	200	Na II	emission	2s2.2p5.(2P<3/2>).3d 2[5/2] → 2s2.2p5.(2P*<3/2>).4f 2[7/2]	Measured	NIST
449.015 nm	200	Na II	emission	2s2.2p5.(2P<3/2>).3d 2[5/2] → 2s2.2p5.(2P*<3/2>).4f 2[7/2]	Measured	NIST
449.088 nm	200	Na II	emission	2s2.2p5.(2P<3/2>).3d 2[5/2] → 2s2.2p5.(2P*<3/2>).4f 2[5/2]	Measured	NIST
449.961 nm	200	Na II	emission	2s2.2p5.(2P<3/2>).3d 2[5/2] → 2s2.2p5.(2P*<3/2>).4f 2[5/2]	Measured	NIST
450.697 nm	200	Na II	emission	2s2.2p5.(2P<3/2>).3d 2[3/2] → 2s2.2p5.(2P*<3/2>).4f 2[5/2]	Measured	NIST
451.92 nm	200	Na II	emission	2s2.2p5.(2P<1/2>).3d 2[3/2] → 2s2.2p5.(2P*<1/2>).4f 2[5/2]	Measured	NIST
452.497 nm	200	Na II	emission	2s2.2p5.(2P<3/2>).3d 2[3/2] → 2s2.2p5.(2P*<3/2>).4f 2[3/2]	Measured	NIST
453.331 nm	200	Na II	emission	2s2.2p5.(2P<3/2>).4s 2[3/2] → 2s2.2p5.(2P*<3/2>).4f 2[5/2]	Measured	NIST
455.152 nm	200	Na II	emission	2s2.2p5.(2P<3/2>).4s 2[3/2] → 2s2.2p5.(2P*<3/2>).4f 2[3/2]	Measured	NIST
391.803 nm	160	Na I	emission	2p5.(2P).3s.3p.(3P) 4D → 2p5.3s.(3P).3d 4F	Measured	NIST
438.42 nm	160	Na II	emission	2s2.2p5.(2P<3/2>).3d 2[7/2] → 2s2.2p5.(2P*<3/2>).4f 2[5/2]	Measured	NIST
439.63 nm	160	Na II	emission	2s2.2p5.(2P<3/2>).3d 2[7/2] → 2s2.2p5.(2P*<3/2>).4f 2[5/2]	Measured	NIST
459.094 nm	160	Na II	emission	2s2.2p5.3p 1S → 2s2.2p5.(2P<3/2>).3d 2[1/2]	Measured	NIST
472.23 nm	160	Na II	emission	2s2.2p5.(2P<1/2>).3d 2[5/2] → 2s2.2p5.(2P*<3/2>).4f 2[7/2]	Measured	NIST
473.113 nm	160	Na II	emission	2s2.2p5.(2P<1/2>).3d 2[5/2] → 2s2.2p5.(2P*<3/2>).4f 2[7/2]	Measured	NIST
474.163 nm	160	Na II	emission	2s2.2p5.(2P<1/2>).3d 2[5/2] → 2s2.2p5.(2P*<3/2>).4f 2[5/2]	Measured	NIST
476.892 nm	160	Na II	emission	2s2.2p5.(2P<1/2>).3d 2[3/2] → 2s2.2p5.(2P*<3/2>).4f 2[5/2]	Measured	NIST
418.546 nm	150	Na I	emission	2p5.(2P).3s.3p.(3P) 4P → 2p5.3s.(3P).3d 4D	Measured	NIST
386.543 nm	130	Na I	emission	2p5.(2P).3s.3p.(3P) 4D → 2p5.3s.(3P).3d 4F	Measured	NIST
408.7593 nm	130	Na II	emission	2s2.2p5.3s 1P* → 2s2.2p5.3p 3S	Measured	NIST
420.2759 nm	130	Na II	emission	2s2.2p5.(2P<3/2>).4s 2[3/2] → 2s2.2p5.(2P*<1/2>).4f 2[5/2]	Measured	NIST

Extended Properties

Covalent Radii (Extended)

Covalent radius (Pyykkö)

Covalent radius (Pyykkö, double)

Covalent radius (Bragg)

Van der Waals Radii

Bondi

Batsanov

Alvarez

UFF

MM3

Atomic & Metallic Radii

Atomic radius (Rahm)

Metallic radius (C12)

Numbering Scales

Mendeleev

Pettifor

Glawe

Electronegativity Scales

Ghosh

Miedema

Gunnarsson–Lundqvist

Robles–Bartolotti

Polarizability & Dispersion

Dipole polarizability

Dipole polarizability (unc.)

C₆

C₆ (Gould–Bučko)

Miedema Parameters

Miedema molar volume

Miedema electron density

Supply Risk & Economics

Production concentration

Relative supply risk

Political stability (top producer)

Phase Transitions & Allotropes

Melting point	370.94 K
Boiling point	1156.09 K
Critical point (temperature)	2573.15 K
Critical point (pressure)	35 MPa

Oxidation State Categories

+1 main

−1 extended

0 extended

Advanced Reference Data

Screening Constants (4)

n	Orbital	σ
1	s	0.3741
2	p	4.1982
2	s	4.4286
3	s	8.4926

Crystal Radii Detail (7)

Charge	CN	r_crystal (pm)	Origin
1	IV	113
1	V	114
1	VI	116
1	VII	126
1	VIII	132
1	IX	138	calculated,
1	XII	153

Isotope Decay Modes (47)

Isotope	Mode	Intensity
17	p	100%
18	p	—
19	p	100%
20	B+	100%
20	B+A	25%
21	B+	100%
22	B+	100%
22	e+	90.6%
22	EC	9.4%
24	B-	100%

X‑ray Scattering Factors (504)

Energy (eV)	f₁	f₂
10	—	0.01475
10.1617	—	0.01517
10.3261	—	0.01559
10.4931	—	0.01603
10.6628	—	0.01648
10.8353	—	0.01695
11.0106	—	0.01743
11.1886	—	0.01792
11.3696	—	0.01842
11.5535	—	0.01894

Additional Data

Estimated Crustal Abundance

The estimated element abundance in the earth's crust.

2.36×104 milligrams per kilogram

References (1)

[5] Sodium https://education.jlab.org/itselemental/ele011.html

Estimated Oceanic Abundance

The estimated element abundance in the earth's oceans.

1.08×104 milligrams per liter

References (1)

[5] Sodium https://education.jlab.org/itselemental/ele011.html

Sources

Sources of this element.

Sodium is present in fair abundance in the sun and stars. The D lines of sodium are among the most prominent in the solar spectrum. Sodium is the fourth most abundant element on earth, comprising about 2.6% of the earth's crust; it is the most abundant of the alkali group of metals.

It is now obtained commercially by the electrolysis of absolutely dry fused sodium chloride. This method is much cheaper than that of electrolyzing sodium hydroxide, as was used several years ago.

References (1)

[6] Sodium https://periodic.lanl.gov/11.shtml

References

(9)

1 PubChem

Data deposited in or computed by PubChem

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2 Atomic Mass Data Center (AMDC), International Atomic Energy Agency (IAEA)

The half-life and atomic mass data was provided by the Atomic Mass Data Center at the International Atomic Energy Agency.

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3 IUPAC Commission on Isotopic Abundances and Atomic Weights (CIAAW)

Sodium

Element data are cited from the Atomic weights of the elements (an IUPAC Technical Report). The IUPAC periodic table of elements can be found at https://iupac.org/what-we-do/periodic-table-of-elements/. Additional information can be found within IUPAC publication doi:10.1515/pac-2015-0703 Copyright © 2020 International Union of Pure and Applied Chemistry.

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4 IUPAC Periodic Table of the Elements and Isotopes (IPTEI)

The information are cited from Pure Appl. Chem. 2018; 90(12): 1833-2092, https://doi.org/10.1515/pac-2015-0703.

Visit source License

License note: Copyright (c) 2020 International Union of Pure and Applied Chemistry. The International Union of Pure and Applied Chemistry (IUPAC) contribution within Pubchem is provided under a CC-BY-NC-ND 4.0 license, unless otherwise stated.

5 Jefferson Lab, U.S. Department of Energy

Sodium

Thomas Jefferson National Accelerator Facility (Jefferson Lab) is one of 17 national laboratories funded by the U.S. Department of Energy. The lab's primary mission is to conduct basic research of the atom's nucleus using the lab's unique particle accelerator, known as the Continuous Electron Beam Accelerator Facility (CEBAF). For more information visit https://www.jlab.org/

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License note: Please see citation and linking information: https://education.jlab.org/faq/index.html

6 Los Alamos National Laboratory, U.S. Department of Energy

Sodium

The periodic table at the LANL (Los Alamos National Laboratory) contains basic element information together with the history, source, properties, use, handling and more. The provenance data may be found from the link under the source name.

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7 NIST Physical Measurement Laboratory

Sodium

The periodic table contains NIST's critically-evaluated data on atomic properties of the elements. The provenance data that include data for atomic spectroscopy, X-ray and gamma ray, radiation dosimetry, nuclear physics, and condensed matter physics may be found from the link under the source name. Ref: https://www.nist.gov/pml/atomic-spectra-database

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8 PubChem Elements

Sodium

This section provides all form of data related to element Sodium.

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9 PubChem Elements

Sodium

The element property data was retrieved from publications.

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Last updated: May 1, 2026