Periodic Table


Atomic number: 11
Atomic weight: 22.9989770
Symbol: Na
Group number: 1
Electronic configuration: [Ne].3s1


Soap is generally a sodium salt of fatty acids. The importance of common salt to animal nutrition has been recognized since prehistoric times. The most common compound is sodium chloride, (table salt).

Sodium is a Group 1 element (or IA in older labelling styles). Group 1 elements are often referred to as the "alkali metals". The chemistry of sodium is dominated by the +1 ion Na+.

General information

Discoveror: Sir Humphrey Davy
Date discovered: 1807
Discovered at: England
Meaning of name: From the English word "soda" (the origin of the symbol Na comes from the Latin word "natrium")

Physical data

Standard state: solid at 298 K
Colour: silvery white/
Density of solid at ambient temperature/kg m-3: 968
Molar volume/cm3: 23.78

Radii /pm

Atomic: 190
Covalent (single bond):
Pauling radius for the ion [Na]-: no data

Valence shell orbital radius maxima (Rmax)
orbital s p d f
radius179.4no datano datano data


Both values are quoted on the Pauling scale.

Pauling: 0.93
Allred Rochow: 1.01

Crystal Structure

structure: bcc (body-centred cubic)

The following CrystalMaker image represents the solid state structure. For most elements, the most stable allotrope is illustrated. Try WebElements version 2 for interactive virtual reality and CHIME images.


Temperatures (/K)

melting point: 370.87
boiling point: 1156

Enthalpies /kJ mol-1

fusion: 2.60
vaporization: 97.7

single bond enthalpies:
Na-F Na-Cl Na-Br Na-I Na-Na
477 408 363 304 73.60

Ionization enthalpies /kJ mol-1

Number Enthalpy


This section gives some data for naturally occurring isotopes.
Nominal mass Accurate mass % natural abundance
23Na22.9897677 (10)100

Further Information

Copyright 1997 Mark Winter
Department of Chemistry at the University of Sheffield, Sheffield S3 7HF, England.

The current version of this document is at http://www.shef.ac.uk/~chem/web-elements-I/Na.html