Sodium

Sodium - Magnesium Li Na K       Full table
General
Name, Symbol, Number	Sodium, Na, 11
Series	Alkali metal
Group, Period, Block	1 (IA), 3 , s
Density, Hardness	968 kg/m3, 0.5
Appearance	silvery white
Atomic Properties
Atomic weight	22.989770 amu
Atomic radius (calc.)	180 (190)pm
Covalent radius	154 pm
van der Waals radius	227 pm
Electron configuration	[Ne]3s1
e- 's per energy level	2, 8, 1
Oxidation states (Oxide)	1 (strong base)
Crystal structure	Cubic body centered
Physical Properties
State of matter	solid (nonmagnetic)
Melting point	370.87 K (207.9 °F)
Boiling point	1156 K (1621 °F)
Molar volume	23.78 ×10-3 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
Miscellaneous
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
iso NA half-life DM DE MeV DP 22Na {syn.} 2.602 y epsilon 2.842 22Ne 23Na 100% Na is stable with 12 neutrons
SI units & STP are used except where noted.

Sodium is a chemical element in the periodic table that has the symbol Na and atom number 11. Sodium is a soft, waxy, silvery reactive metal belonging to the alkali metals that is abundant in natural compounds (especially salt water and halite[?]). It is highly reactive, burns with a yellow flame, oxidizes in air and reacts violently with water, forcing it to be kept under oil.

Table of contents 1 Notable Characteristics 2 Applications 3 History 4 Occurrence 5 Compounds 6 Isotopes 7 Precautions 8 External Links

Notable Characteristics 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. Applications 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.

NaK, an alloy of sodium and potassium, is an important heat transfer material.

History 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.

Occurrence 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):
Compounds 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 (NaHCO₃), caustic soda (NaOH), Chile saltpeter (NaNO₃), di- and tri-sodium phosphates, sodium thiosulfate[?] (hypo, Na₂S₂O_{3 *} 5H₂O), and borax (Na₂B₄O_{7 *} 10H₂O). Isotopes 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). Precautions 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 cannot be maintained in an inert atmosphere and contact with water and other substances that sodium reacts with should be avoided.

External Links

• WebElements.com - Sodium (http://www.webelements.com/webelements/elements/text/Na/index)
• EnvironmentalChemistry.com - Sodium (http://environmentalchemistry.com/yogi/periodic/Na)