Oxygen

:This article is about the chemical element oxygen. For other usage, see Oxygen (disambiguation).

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:Newspapers sometimes say "oxygen cylinders" as an inaccurate reference to scuba gear.

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Oxygen is a chemical element in the periodic table. It has the symbol O and atomic number 8. The element is very common, found not only on Earth but throughout the universe, usually bound with other elements. Unbound oxygen (usually called molecular oxygen, O2) appeared on Earth first as a product of the metabolic action of early anaerobes (archaea and bacteria). The atmospheric abundance of free oxygen in later geological epochs and up to the present has been largely driven by photosynthetic organisms, roughly three quarters by phytoplankton and algae in the oceans and one quarter from terrestrial plants.

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Chemical element: A chemical element, often called simply element, is the class of atoms which contain the same number of protons....

Periodic table: The periodic table of the chemical elements, also called the Mendeleev periodic table, is a tabular display of the known chemical elements. First created by Dmitri Mendeleev, the elements are arranged by electron configuration so that many chemical properties follow a regular pattern across the tabl...

Atomic number: The atomic number (Z) is a term used in chemistry and physics to represent the number of protons found in the nucleus of an atom. In an atom of neutral charge, the number of electrons typically equals the atomic number....

Oxygen related Images and Photos (experimental)

Oxygen IV	Oxygen IV	Oxygen Yoga Mat	Oxygen Flower Trio
Oxygen Scribble Flower	Oxygen Obsessed Key Chain	Mountain Climbing at High Altitude Using Oxygen Masks with the Cylinders Strapped to Their Backs