This article is about the chemical element. For the nutrient commonly called sodium, see salt. For the use of sodium as a medication, see Saline (medicine). For other uses, see sodium (disambiguation).
"Natrium" redirects here. For other uses, see Natrium (disambiguation).
Chemical element, symbol Na and atomic number 11
Sodium, 11Na
Sodium
Appearance
silvery white metallic
Standard atomic weight Ar°(Na)
22.98976928±0.00000002[1]
22.990±0.001 (abridged)[2]
Sodium in the periodic table
Hydrogen
Helium
Lithium
Beryllium
Boron
Carbon
Nitrogen
Oxygen
Fluorine
Neon
Sodium
Magnesium
Aluminium
Silicon
Phosphorus
Sulfur
Chlorine
Argon
Potassium
Calcium
Scandium
Titanium
Vanadium
Chromium
Manganese
Iron
Cobalt
Nickel
Copper
Zinc
Gallium
Germanium
Arsenic
Selenium
Bromine
Krypton
Rubidium
Strontium
Yttrium
Zirconium
Niobium
Molybdenum
Technetium
Ruthenium
Rhodium
Palladium
Silver
Cadmium
Indium
Tin
Antimony
Tellurium
Iodine
Xenon
Caesium
Barium
Lanthanum
Cerium
Praseodymium
Neodymium
Promethium
Samarium
Europium
Gadolinium
Terbium
Dysprosium
Holmium
Erbium
Thulium
Ytterbium
Lutetium
Hafnium
Tantalum
Tungsten
Rhenium
Osmium
Iridium
Platinum
Gold
Mercury (element)
Thallium
Lead
Bismuth
Polonium
Astatine
Radon
Francium
Radium
Actinium
Thorium
Protactinium
Uranium
Neptunium
Plutonium
Americium
Curium
Berkelium
Californium
Einsteinium
Fermium
Mendelevium
Nobelium
Lawrencium
Rutherfordium
Dubnium
Seaborgium
Bohrium
Hassium
Meitnerium
Darmstadtium
Roentgenium
Copernicium
Nihonium
Flerovium
Moscovium
Livermorium
Tennessine
Oganesson
Li ↑ Na ↓ K
neon ← sodium → magnesium
Atomic number (Z)
11
Group
group 1: hydrogen and alkali metals
Period
period 3
Block
s-block
Electron configuration
[Ne] 3s1
Electrons per shell
2, 8, 1
Physical properties
Phase at STP
solid
Melting point
370.944 K (97.794 °C, 208.029 °F)
Boiling point
1156.090 K (882.940 °C, 1621.292 °F)
Density (at 20° C)
0.9688 g/cm3[3]
when liquid (at m.p.)
0.927 g/cm3
Critical point
2573 K, 35 MPa (extrapolated)
Heat of fusion
2.60 kJ/mol
Heat of vaporization
97.42 kJ/mol
Molar heat capacity
28.230 J/(mol·K)
Vapor pressure
P(Pa)
1
10
100
1 k
10 k
100 k
at T(K)
554
617
697
802
946
1153
Atomic properties
Oxidation states
−1, 0,[4]+1 (a strongly basic oxide)
Electronegativity
Pauling scale: 0.93
Ionization energies
1st: 495.8 kJ/mol
2nd: 4562 kJ/mol
3rd: 6910.3 kJ/mol
(more)
Atomic radius
empirical: 186 pm
Covalent radius
166±9 pm
Van der Waals radius
227 pm
Spectral lines of sodium
Other properties
Natural occurrence
primordial
Crystal structure
body-centered cubic (bcc) (cI2)
Lattice constant
a = 428.74 pm (at 20 °C)[3]
Thermal expansion
69.91×10−6/K (at 20 °C)[3]
Thermal conductivity
142 W/(m⋅K)
Electrical resistivity
47.7 nΩ⋅m (at 20 °C)
Magnetic ordering
paramagnetic[5]
Molar magnetic susceptibility
+16.0×10−6 cm3/mol (298 K)[6]
Young's modulus
10 GPa
Shear modulus
3.3 GPa
Bulk modulus
6.3 GPa
Speed of sound thin rod
3200 m/s (at 20 °C)
Mohs hardness
0.5
Brinell hardness
0.69 MPa
CAS Number
7440-23-5
History
Discovery and first isolation
Humphry Davy (1807)
Symbol
"Na": from New Latin natrium, coined from German Natron, 'natron'
Isotopes of sodium
v
e
Main isotopes[7]
Decay
abundance
half-life (t1/2)
mode
product
22Na
trace
2.6019 y
β+
22Ne
23Na
100%
stable
24Na
trace
14.9560 h
β−
24Mg
Category: Sodium
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Sodium is a chemical element; it has symbol Na (from Neo-Latin natrium) and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 of the periodic table. Its only stable isotope is 23Na. The free metal does not occur in nature and must be prepared from compounds. Sodium is the sixth most abundant element in the Earth's crust and exists in numerous minerals such as feldspars, sodalite, and halite (NaCl). Many salts of sodium are highly water-soluble: sodium ions have been leached by the action of water from the Earth's minerals over eons, and thus sodium and chlorine are the most common dissolved elements by weight in the oceans.
Sodium was first isolated by Humphry Davy in 1807 by the electrolysis of sodium hydroxide. Among many other useful sodium compounds, sodium hydroxide (lye) is used in soap manufacture, and sodium chloride (edible salt) is a de-icing agent and a nutrient for animals including humans.
Sodium is an essential element for all animals and some plants. Sodium ions are the major cation in the extracellular fluid (ECF) and as such are the major contributor to the ECF osmotic pressure and ECF compartment volume.[citation needed] Loss of water from the ECF compartment increases the sodium concentration, a condition called hypernatremia. Isotonic loss of water and sodium from the ECF compartment decreases the size of that compartment in a condition called ECF hypovolemia.
By means of the sodium–potassium pump, living human cells pump three sodium ions out of the cell in exchange for two potassium ions pumped in; comparing ion concentrations across the cell membrane, inside to outside, potassium measures about 40:1, and sodium, about 1:10. In nerve cells, the electrical charge across the cell membrane enables transmission of the nerve impulse—an action potential—when the charge is dissipated; sodium plays a key role in that activity.
^"Standard Atomic Weights: Sodium". CIAAW. 2005.
^Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; Böhlke, John K.; Chesson, Lesley A.; Coplen, Tyler B.; Ding, Tiping; Dunn, Philip J. H.; Gröning, Manfred; Holden, Norman E.; Meijer, Harro A. J. (4 May 2022). "Standard atomic weights of the elements 2021 (IUPAC Technical Report)". Pure and Applied Chemistry. doi:10.1515/pac-2019-0603. ISSN 1365-3075.
^ abcArblaster, John W. (2018). Selected Values of the Crystallographic Properties of Elements. Materials Park, Ohio: ASM International. ISBN 978-1-62708-155-9.
^The compound NaCl has been shown in experiments to exists in several unusual stoichiometries under high pressure, including Na3Cl in which contains a layer of sodium(0) atoms; see Zhang, W.; Oganov, A. R.; Goncharov, A. F.; Zhu, Q.; Boulfelfel, S. E.; Lyakhov, A. O.; Stavrou, E.; Somayazulu, M.; Prakapenka, V. B.; Konôpková, Z. (2013). "Unexpected Stable Stoichiometries of Sodium Chlorides". Science. 342 (6165): 1502–1505. arXiv:1310.7674. Bibcode:2013Sci...342.1502Z. doi:10.1126/science.1244989. PMID 24357316. S2CID 15298372.
^Magnetic susceptibility of the elements and inorganic compounds, in Lide, D. R., ed. (2005). CRC Handbook of Chemistry and Physics (86th ed.). Boca Raton (FL): CRC Press. ISBN 0-8493-0486-5.
^Weast, Robert (1984). CRC, Handbook of Chemistry and Physics. Boca Raton, Florida: Chemical Rubber Company Publishing. pp. E110. ISBN 0-8493-0464-4.
^Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae.
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