Sodium

Figure 1. Sodium, with atomic number 11 and atomic weight of 22.990.

Sodium is the 11^th element on the periodic table of elements, and is the sixth most common element on the Earth, makinng up 2.6% of the crust. Some of its properties are listed below:

Atomic weight	22.990
Density (at 0oC)	0.97 g/cm3
Boiling point	1156.090 K
Melting point	370.944 K

Sodium is a soft, easily tarnished, alkali metal. It is not found as a pure metal in nature due to its highly reactive nature. Sodium is so highly reactive that it can cause explosions with just water (see video below). Sodium is an essential component of many common minerals (e.g. feldspar and rock salt). It is also an important element for humans and animals to maintain healthy body functions.

Sodium Uses

Figure 1. Sodium metal.

Sodium salts have more uses than the pure metal. Sodium chloride (NaCl) the most common form of salt, including the salt that is added to food, for de-icing, and as salt blocks for animals. Sodium compounds are often used as part of various reagents in chemistry.

The metal is sometimes used to remove heat from nuclear reactors, particularly sodium-cooled fast breeder reactors. Sodium makes an ideal coolant for a fast reactors because the liquid can operate at high temperatures without high pressure. Sodium is a plentiful, relatively cheap metal that causes minimal corrosion on the reactor equipment and is easily purified.

Isotopes

Sodium has one isotope found in nature:

Symbol	Natural Abundance
23Na	100%

Video

The video below is from the University of Nottingham's periodic videos project. They have created a complete suite of short videos on every element on the periodic table of elements.

Here is a historic video showing the explosions that happen when large amounts of sodium are put in water:

For Further Reading

• Periodic table of elements
• Metal
• Nuclear reactor
• Mineral
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