Sodium

Sodium, ₀₀Na
Sodium
Appearance	silvery white metallic
Standard atomic weight Ar°(Na)
	22.98976928(2)
Sodium in the periodic table
	neon ← sodium → magnesium
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 (near r.t.)	0.968 g/cm3
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)
Atomic properties
Oxidation states	−1, 0, +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)
Speed of sound thin rod	3200 m/s (at 20 °C)
Thermal expansion	71 µm/(m⋅K) (at 25 °C)
Thermal conductivity	142 W/(m⋅K)
Electrical resistivity	47.7 nΩ⋅m (at 20 °C)
Magnetic ordering	paramagnetic
Molar magnetic susceptibility	+16.0·10−6 cm3/mol (298 K)
Young's modulus	10 GPa
Shear modulus	3.3 GPa
Bulk modulus	6.3 GPa
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;
	Category: Sodium; view; talk; edit; \| references

Sodium is a chemical element with an atomic number of 11. Its symbol is Na (from its Latin name natrium). It is an alkali metal. Although sodium has many isotopes, most decay in a short time. Because of this, all sodium in nature (mainly found in sea water) is of the isotope ₁₁Na²³. The atomic mass of sodium is 22.9898.

Properties

Sodium is a light, silver-colored metal. Sodium is soft, because of that it can easily be cut with a knife. When it is cut, the exposed surface will become white over time. That is because it reacts with air to form sodium hydroxide and sodium carbonate. Sodium is slightly less dense than water; when it is put in water, it floats and reacts instantly, producing hydrogen and sodium hydroxide. This reaction is quick and produces a lot of heat, usually causing the hydrogen to ignite. When this reaction happens, sodium melts because of its low melting point. Sodium is highly reactive because it has one valence electron, which is easily removed.

Compared with other alkali metals, sodium is less reactive than potassium and more reactive than lithium.^[6]

Chemical compounds

These are chemical compounds that contain sodium ions. Sodium only exists in one oxidation state: +1.

Sodium aluminum fluoride, used to make aluminum
Sodium amide, very strong base
Sodium arsenite, colorless solid, very toxic
Sodium arsenate, oxidizing agent, very toxic
Sodium azide, used in airbags
Sodium bicarbonate, baking soda, used in cooking
Sodium bismuthate, oxidizing agent, used to test for manganese
Sodium bisulfate, acidic, used to lower pH
Sodium bromate, oxidizing agent, used to dye hair
Sodium bromide, rare, used in some medicine
Sodium carbonate, used to make glass
Sodium chlorate, used in some explosives
Sodium chlorite, used in disinfectants
Sodium chloride, table salt
Sodium chromate, yellow, oxidizing agent, toxic
Sodium dichromate, orange, oxidizing agent, toxic
Sodium fluoride, used in toothpastes, bitter, toxic in large doses
Sodium hydroxide, lye, used in soap, strong base
Sodium hypochlorite, bleach, disinfectant
Sodium hypophosphite, reducing agent, poisonous
Sodium iodate, oxidizing agent, prevents iodine deficiency
Sodium iodide, weak reducing agent, prevents iodine deficiency
Sodium manganate, rare green solid
Sodium nitrate, used in blasting powder
Sodium nitrite, used in food preservation
Sodium periodate, oxidizing agent
Sodium permanganate, less common than potassium permanganate, oxidizing agent
Sodium phosphate, various uses
Sodium phosphide, catalyst, used to speed up chemical reactions
Sodium phosphite, toxic, reducing agent
Sodium selenate, strong oxidizing agent, other selenium compounds
Sodium selenide, strong reducing agent, reactive
Sodium selenite, weak oxidizing agent, vitamin supplement
Sodium sulfate, bitter, laxative
Sodium sulfite, weak reducing agent, used to preserve dried food
Sodium tellurate, strong oxidizing agent
Sodium telluride, strong reducing agent, reacts with air easily
Sodium tellurite, main tellurite compound

Discovery and name origins

Sodium was discovered by Sir Humphrey Davy, an English scientist, in 1807. He synthesized it by electrolysing sodium hydroxide. It is named after soda, a name for sodium hydroxide or sodium carbonate.

Related pages

List of common elements
Hyponatremia (a medical problem caused by not having enough sodium in the body)

References

↑ "Standard Atomic Weights: Sodium". CIAAW. 2005.
↑ 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.
↑ De Leon, N. "Reactivity of Alkali Metals". Indiana University Northwest. Archived from the original on 2018-10-16. Retrieved 2007-12-07.

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[1] "Standard Atomic Weights: Sodium". CIAAW. 2005.

[2] 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.

[3] 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.

[4] Weast, Robert (1984). CRC, Handbook of Chemistry and Physics. Boca Raton, Florida: Chemical Rubber Company Publishing. pp. E110. ISBN 0-8493-0464-4.

[NUBASE2020-5] 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.

[6] De Leon, N. "Reactivity of Alkali Metals". Indiana University Northwest. Archived from the original on 2018-10-16. Retrieved 2007-12-07.

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