The chemical element Sodium

Sodium

Symbol: Na

Atomic Number: 11

Atomic Mass: 22.98977 amu (atomic mass units)

Melting Point: 97.72 °C (370.87 K, 207.9 °F)

Boiling Point: 883 °C (1156 K, 1621 °F)

Number of Protons: 11

Number of Electrons: 11

Number of Neutrons: 12

Classification: Metal

Group Name: Alkali Metal

Crystal Structure: Cubic

Density @ 293 K: 0.971 grams per cubic centimeter

Color: silver

This very reactive alkali metal was discovered by the British scientist Sir Humphrey Davy in 1807. The name of the element comes from soda (Na2CO3) as well as from the Medieval Latin word “sodanum” which meant headache remedy. The symbol Na comes from the Latin for sodium carbonate “natrium”.

Sodium metal is extremely soft and can be cut easily with a knife. The sodium atom has only one electron in its outer shell which it will easily give up to an atom of another element to form an ionic bond. It will react violently, producing hydrogen which can ignite, when brought into contact with water. To prevent it reacting with water vapor in the air the pure metal is normally stored under a mineral oil. Because it is so reactive it has never been found naturally in its metallic state but always as a compound. It is not the most reactive of the alkali metals as potassium, rubidium and cesium are all more reactive than sodium.

It is the sixth most abundant element found on earth making up 2.6% of the earths crust with an estimated crustal abundance of 2.36 grams per kilogram. Within the earths oceans it has an estimated abundance of 1.08 grams per liter.

The element has only one naturally occurring isotope that is sodium-23. Sodium-23 is a stable isotope. A number of unstable isotopes of sodium have been produced with mass numbers which range from 18 to 35. Sodium-19 has the shortest half-life at less than 40 nanoseconds it decays by proton emission. The isotope with the longest half-life is sodium-22 at 2.6019 years it decays by electron capture.

Sodium is found in a number of common useful compounds such as salt (NaCl), caustic soda (NaOH), baking soda (NaHCO3) and borax (Na2B4O7.10H2O).

Within industry sodium is used in the production of sodium peroxide, sodium hydride, sodamide, sodium cyanide and titanium. The yellow color seen in many street lamps is due to the presence of sodium vapor within the bulbs. The nuclear power industry uses liquid sodium as a coolant for reactors.