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{{Infobox sodium}}
[[File:Sodium.jpg|thumb|Sodium pellets in a container]]
'''Sodium''' is a [[chemical element]] with an [[atomic number]] of 11. Its symbol is '''Na''' (from its Latin name ''natrium''). It is an [[alkali metal]]. Although sodium has many [[isotope]]s, most decay in a short time. Because of this, all sodium in nature (mainly found in [[seawater]]) is of the isotope <sub>11</sub>Na<sup>23</sup>. The [[atomic mass]] of sodium is 22.9898.

== Properties ==
Sodium is a light-weight, [[silver]]-colored [[metal]]. Sodium is soft. It can easily be cut with a knife. When someone cuts it, the exposed part will become white over time. It reacts with air to form, at first [[sodium oxide]], then slowly [[sodium hydroxide]] and [[sodium carbonate]]. Sodium is a little less [[Density|dense]] than water. It floats and reacts instantly with water, producing [[hydrogen]] and [[sodium hydroxide]]. This reaction makes a lot of heat, usually causing the hydrogen to light on fire. When this happens, sodium melts because of its low melting point. Sodium is highly reactive because it has one [[valence electron]], which is easily removed.  

Compared with other [[Alkali metal|alkali metals]], sodium is less reactive than [[potassium]] and more reactive than [[lithium]].<ref>{{cite web|author=De Leon, N.|title=Reactivity of Alkali Metals|url=http://www.iun.edu/~cpanhd/C101webnotes/modern-atomic-theory/alkali-reac.html|publisher=[[Indiana University Northwest]]|accessdate=2007-12-07|archive-date=2018-10-16|archive-url=https://web.archive.org/web/20181016113143/http://www.iun.edu/~cpanhd/C101webnotes/modern-atomic-theory/alkali-reac.html|url-status=dead}}</ref>

== Chemical compounds ==
These are [[chemical compound]]s that contain sodium [[ion]]s. Sodium only exists in one [[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 lower 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 toothpaste, bitter, toxic in large doses
*[[Sodium hydroxide]], lye, used in soap, strong [[base (chemistry)|base]]
*[[Sodium hypochlorite]], bleach, disinfectant
*[[Sodium hypophosphite]], [[reducing agent]], poisonous
*[[Sodium iodate]], oxidizing agent, prevents iodine deficiency
*[[Sodium iodide]], a 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]], [[Catalysis|catalyst]], used to speed up chemical reactions
*[[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]], a weak reducing agent, used to preserve dried food
*[[Sodium tellurate]], strong oxidizing agent
*[[Sodium telluride]], a strong reducing agent, reacts with air easily
*[[Sodium tellurite]], main tellurite compound

== Discovery and name origins ==
Sodium was discovered by Sir Humphrey Davy, an English scientist, in 1807. He created it by [[Electrolysis|electrolyzing]] sodium hydroxide. Davy named the element after [[soda]], a name for sodium hydroxide or [[sodium carbonate]].
== Uses ==
Scientists can use it in the creation of [[Organic compound|organic compounds]]. It is used  in orange [[Streetlight|streetlights]] and lamps that emit [[ultraviolet]] light.

Sodium compounds are used in [[Soap|soaps]], [[toothpaste]], [[baking]], and [[antacid]]s.

The [[human body]] needs sodium [[Ion|ions]], taken in the form of [[Table salt|sodium chloride]], to live. Too much of it can cause health problems. Many organisms in the ocean depend on the [[concentration]] of sodium ions in water to survive.

== Occurrence and production ==
Sodium does not occur as an element in nature, because it is not stable enough. It exists only in [[chemical compound]]s. Sodium [[Ion|ions]] are found in the ocean and in the [[Earth's crust]]. 

Sodium is normally made by [[electrolysis]] of [[sodium chloride]], which is mined from the Earth's crust.
==Related pages==
* [[List of common elements]]
* [[Hyponatremia]] (a medical problem caused by not having enough sodium in the body)
== References ==
{{reflist}}

{{Periodic Table}}

[[Category:Alkali metals]]

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