Isotope	Abundance	Half-life (t_1/2)	Decay mode	Product
²²Na	trace	2.602 y	β⁺→γ	0.5454	²²Ne*
			β⁺→γ	1.27453(2)	²²Ne
			ε→γ	-	²²Ne*
			ε→γ	1.27453(2)	²²Ne
			β⁺	1.8200	²²Ne
²³Na	100%	²³Na is stable with 12 neutrons

Sodium pellets in a container

Sodium is a chemical element with the symbol Na (from Latin natrium) and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 of the periodic table, because it has a single electron in its outer shell, which it readily donates, creating a positively charged ion—the Na⁺ cation. Its only stable isotope is Na. The free metal does not occur in nature, and must be prepared from compounds. Sodium is the sixth most abundant element in the Earth's crust and exists in numerous minerals such as feldspars, sodalite, and rock salt (NaCl). Many salts of sodium are highly water-soluble: sodium ions have been leached by the action of water from the Earth's minerals over eons, and thus sodium and chlorine are the most common dissolved elements by weight in the oceans.

Sodium was first isolated by Humphry Davy in 1807 by the electrolysis of sodium hydroxide. Among many other useful sodium compounds, sodium hydroxide (lye) is used in soap manufacture, and sodium chloride (edible salt) is a de-icing agent and a nutrient for animals including humans.

Sodium is an essential element for all animals and some plants. Sodium ions are the major cation in the extracellular fluid (ECF) and as such are the major contributor to the ECF osmotic pressure and ECF compartment volume. Loss of water from the ECF compartment increases the sodium concentration, a condition called hypernatremia. Isotonic loss of water and sodium from the ECF compartment decreases the size of that compartment in a condition called ECF hypovolemia.

Properties
- Chemical compounds
Discovery and name
Use as element
Use as compounds
Occurrence and production
Use in organisms
Related pages
Images for kids
See also

Properties

Sodium is a light, silver-coloured metal. Sodium is so soft that it can be easily cut with a knife. When it is cut, the surface will become white after a bit of time. This is because it reacts with air to form sodium hydroxide and sodium carbonate. Sodium is a little lighter than water; when it reacts with water it floats. This reaction is very fast. Hydrogen and sodium hydroxide are produced. The hydrogen may ignite. Since sodium melts at a low temperature, it melts when it reacts with water. It has one valence electron which is removed easily, making it highly reactive.

Compared with other alkali metals (metals in the first column of the periodic table), sodium is usually less reactive than potassium and more reactive than lithium.

Chemical compounds

These are chemical compounds that contain sodium ions. Sodium only exists in 1 oxidation state: +1.

Sodium aluminum fluoride, used to make aluminum
Sodium amide, very strong base
Sodium arsenite, colorless solid, very toxic
Sodium arsenate, oxidizing agent, very toxic
Sodium azide, used in airbags
Sodium bicarbonate, baking soda, used in cooking
Sodium bismuthate, oxidizing agent, used to test for manganese
Sodium bisulfate, acidic, used to increase pH
Sodium bromate, oxidizing agent, used to dye hair
Sodium bromide, rare, used in some medicine
Sodium carbonate, used to make glass
Sodium chlorate, used in some explosives
Sodium chlorite, used in disinfectants
Sodium chloride, table salt
Sodium chromate, yellow, oxidizing agent, toxic
Sodium dichromate, orange, oxidizing agent, toxic
Sodium fluoride, used in toothpastes, bitter, toxic in large doses
Sodium hydroxide, lye, used in soap, strong base
Sodium hypochlorite, bleach, disinfectant
Sodium hypophosphite, reducing agent, poisonous
Sodium iodate, oxidizing agent, prevents iodine deficiency
Sodium iodide, weak reducing agent, prevents iodine deficiency
Sodium manganate, rare green solid
Sodium nitrate, used in blasting powder
Sodium nitrite, used in food preservation
Sodium periodate, oxidizing agent
Sodium permanganate, less common than potassium permanganate, oxidizing agent
Sodium phosphate, various uses
Sodium phosphide, catalyst
Sodium phosphite, toxic, reducing agent
Sodium selenate, strong oxidizing agent, other selenium compounds
Sodium selenide, strong reducing agent, reactive
Sodium selenite, weak oxidizing agent, vitamin supplement
Sodium sulfate, bitter, laxative
Sodium sulfite, weak reducing agent, used to preserve dried food
Sodium tellurate, strong oxidizing agent
Sodium telluride, strong reducing agent, reacts with air easily
Sodium tellurite, main tellurite compound

Discovery and name

Sodium was discovered by Sir Humphrey Davy, an English scientist, back in 1807. He made it by the electrolysis of sodium hydroxide. It is named after soda, a name for sodium hydroxide or sodium carbonate.

Use as element

It is used in the preparation of organic compounds. It is also used in the street lights that are orange, and ultra violet lights.

Use as compounds

Sodium compounds are used in soaps, toothpaste, baking and antiacids. .

Occurrence and production

Sodium does not exist as an element in nature; its easily removed valence electron is too reactive. It exists as an ion in chemical compounds. Sodium ions are found in the ocean. It is also found as sodium chloride in the earth's crust, where it is mined.

Sodium is normally made by electrolysis of very hot sodium chloride that was melted.

Use in organisms

Sodium ion in the form of sodium chloride is needed in the human body, but large amounts of it cause problems, which is why one should not eat too much salt. Many organisms in the ocean depend on the proper concentration of ions in sea water to live.

List of common elements
Hyponatremia (a medical problem caused by not having enough sodium in the body)

Images for kids

Emission spectrum for sodium, showing the D line.
A positive flame test for sodium has a bright yellow color.
The structure of sodium chloride, showing octahedral coordination around Na+ and Cl− centres. This framework disintegrates when dissolved in water and reassembles when the water evaporates.
Two equivalent images of the chemical structure of sodium stearate, a typical soap.
The structure of the complex of sodium (Na+, shown in yellow) and the antibiotic monensin-A.

Sodium facts for kids

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