Symbol: O

Atomic number: 8

Average atomic mass: 15.9994


When oxygen is a gas, it is colorless, but when it is a liquid, it is pale blue.
Oxygen is also classified as non-metallic. The standard state of this gas is 298K


It is essential for respiration of all plants and animals and for most types of combustion.


Oxygen was dicovered in 1774 by two men named Joseph Priestly and Carl Scheele in England, Sweden. Oxygen in greek means acid former. While about one fifth of the atmosphere is oxygen gas, the atmosphere of Mars contains only about 0.15% oxygen. Oxygen is the third most abundant element found in the sun.

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