|Type:Alkali Metal||Atomic weight:22.98977|
|Density @ 293 K: 0.971 g/cm3||Atomic volume:23.7 cm3/mol|
In 1806 Sir Humphry Davy had discovered that chemical bonding was electrical in nature and that he could use electricity to split substances into their constituent elements. In 1807 he isolated sodium for the first time by electrolysis of molten sodium hydroxide.
|State (s, l, g):solid|
|Melting point:370.87 K (97.72 °C)||Boiling point:1156 K (883 °C)|
|Specific heat capacity: 1.23 J g-1 K-1||Heat of atomization:107 kJ mol-1|
|Heat of fusion:2.598 kJ mol-1||Heat of vaporization :96.960 kJ mol-1|
|1st ionization energy: 495.8 kJ mol-1||2nd ionization energy:4562.4 kJ mol-1|
|3rd ionization energy:6912.2 kJ mol-1||Electron affinity:52.868 kJ mol-1|
|Shells:2,8,1||Electron configuration: [Ne] 3s1|
|Minimum oxidation number:-1||Maximum oxidation number: 1|
|Min. common oxidation no.:0||Max. common oxidation no.: 1|
|Electronegativity (Pauling Scale): 0.93||Polarizability volume: 23.6 Å3|
|Structure:bcc: body-centered cubic||Color:silvery-white|
Sodium is considered to be non-toxic. Contact with the skin may, however, cause irritation and burns.
Sodium is a soft, silvery-white metal. It is soft enough to cut with the edge of a coin.
Metallic sodium is used in the manufacture of sodamide and esters, and in the preparation of organic compounds. The metal also may be used to modify alloys such as aluminum-silicon by improving their mechanical properties and fluidity. Sodium is used to descale (smooth the surface of) metals and to purify molten metals.
|Reaction with air:vigorous, ⇒ Na2O2||Reaction with 6 M HCl:vigorous, ⇒ H2, NaCl|
|Reaction with 15 M HNO3:vigorous, ⇒ NaNO3, NOx||Reaction with 6 M NaOH:vigorous, ⇒ H2, NaOH|
|Atomic radius:186 pm||Ionic radius (1+ ion):116 pm|
|Ionic radius (2+ ion):pm||Ionic radius (3+ ion):pm|
|Ionic radius (2- ion):pm||Ionic radius (1- ion):pm|
|Thermal conductivity:142 W m-1 K-1||Electrical conductivity:0.21 x 106 S cm-1|
|Abundance earth's crust:2.4 % by weight, 2.1 % by moles|
|Abundance solar system:40 parts per million by weight, 2 parts per million by moles|
|Cost, pure: $25 per 100g|
|Cost, bulk:$ per 100g|
Due to its high reactivity, sodium is found in nature only as a compound and never as the free element. Sodium is our planet's sixth most abundant element and it is the most abundant alkali metal. Sodium is obtained commercially by electrolysis of molten sodium chloride.
Sodium has 16 isotopes whose half-lives are known, with mass numbers 20 to 35. Of these, only one is stable: 23Na.