|Name, Symbol, Number||Sodium, Na, 11|
|Group, Period, Block||1 (IA), 3 , s|
|Density, Hardness||968 kg/m3, 0.5|
|Atomic weight||22.989770 amu|
|Atomic radius (calc.)||180 (190)pm|
|Covalent radius||154 pm|
|van der Waals radius||227 pm|
|e- 's per energy level||2, 8, 1|
|Oxidation states (Oxide)||1 (strong base)|
|Crystal structure||Cubic body centered|
|State of matter||solid (nonmagnetic)|
|Melting point||370.87 K (207.9 °F)|
|Boiling point||1156 K (1621 °F)|
|Molar volume||23.78 ×1010-3 m3/mol|
|Heat of vaporization||96.96 kJ/mol|
|Heat of fusion||2.598 kJ/mol|
|Vapor pressure||1.43×10-5Pa at 1234 K|
|Speed of sound||3200 m/s at 293.15 K|
|Electronegativity||0.93 (Pauling scale)|
|Specific heat capacity||1230 J/(kg*K)|
|Electrical conductivity||21 106/m ohm|
|Thermal conductivity||141 W/(m*K)|
|1st ionization potential||495.8 kJ/mol|
|2nd ionization potential||4562 kJ/mol|
|3rd ionization potential||6910.3 kJ/mol|
|4th ionization potential||9543 kJ/mol|
|5th ionization potential||13354 kJ/mol|
|6th ionization potential||16613 kJ/mol|
|7th ionization potential||20117 kJ/mol|
|8th ionization potential||25496 kJ/mol|
|9th ionization potential||28932 kJ/mol|
|10th ionization potential||141362 kJ/mol|
|Most Stable Isotopes|
|SI units & STP are used except where noted.|
|Table of contents|
8 Physiology and Na+ ions
9 External Links
Like the other alkali metals, sodium is a soft, light-weight, silvery white, reactive element that is never found unbound in nature. Sodium floats in water and decomposes it releasing hydrogen and forming hydroxide. If ground to a fine enough power, sodium will ignite spontaneously in water. However, this metal does not normally ignite in air below 388 Kelvin.
Sodium in its metallic form is an essential component in the making of esters and in the manufacture of organic compounds. This alkali metal is also a component of sodium chloride (NaCl) which is vital to life. Other uses:
- In certain alloys to improve their structure,
- In soap (in combination with fatty acids),
- To descale (make its surface smooth) metal, and
- To purify molten metals.
Sodium (English, soda) has long been recognized in compounds, but was not isolated until 1807 by Sir Humphry Davy through the electrolysis of caustic soda. In Medieval Europe a compound of sodium with the Medieval Latin name of sodanum was used as a headache remedy. Sodium's symbol, Na, comes for the neo-Latin name for a common sodium compound named Natrium, which comes from the Greek nítron, a kind of natural salt.
Sodium is relatively abundant in stars and the D spectral lines of this element are among the most prominent in star light. Sodium makes up about 2.6% of the Earth's crust making it the fourth most abundant element overall and the most abundant alkali metal. It is now produced commercially through the electrolysis of completely dry fused sodium chloride. This method is less expensive than the previous method of electrolyzing sodium hydroxide. Metallic sodium cost about 15 to 20 US cents per pound in 1997 but reagent grade (ACS) sodium cost about US$35 per pound in 1990. It is the cheapest of all metals by volume.
Isolation (* follow):
Sodium chloride, better known as common salt, is the most common compound of sodium, but sodium occurs in many other minerals, such as amphibole, cryolite, halite, soda niter, zeolite, etc. Sodium compounds are important to the chemical, glass, metal, paper, petroleum, soap, and textile industries. Soap is generally a sodium salt of certain fatty acids.
The sodium compounds that are the most important to industry are common salt (NaCl), soda ash (Na2CO3), baking soda (NaHCOCO3), caustic soda (NaOH), Chile saltpeter (NaNOO3), di- and tri-sodium phosphates, sodium thiosulfate (hypo, Na2S2O3 * 5H2O), and borax (Na2B4O7 * 10H2O).
There are thirteen isotopes of sodium that have been recognized. The only stable isotope is Na-23. Sodium has two radioactive cosmogenic isotopes (Na-22, half-life = 2.605 years; Na-24, half-life = ~ 15 hours).
In its powdered form sodium is explosive in water and a poison combined and uncombined with many other elements. This metal should be handled carefully at all times. Sodium must be be maintained in an inert atmosphere and contact with water and other substances that sodium reacts with should be avoided.