Oxygen is the simplest group VIA element and is, under normal atmospheric conditions, usually found as a colorless, odorless, and tasteless gas. Oxygen has an atomic number of 8 and an atomic mass of 16.0 amu. The liquid and solid forms, which are strongly paramagnetic, are a pale blue color. Oxygen has a boiling point of −297°F (−182.8°C) and a melting point of −368.7°F (−222.6°C).

Oxygen is the third most abundant element found in the Sun, after hydrogen and helium, and plays an important role in the carbon-nitrogen cycle. Oxygen composes 21% of Earth's atmosphere by volume and is vital to the existence of carbon-based life forms.

Although English chemist Joseph Priestley (1733–1804) is generally credited with the discovery of oxygen in 1774, many science historians contend that Swedish chemist Carl Scheele (1742–1786) probably discovered oxygen a few years prior to Priestly. French chemist Antoine Lavoisier's (1743–1794) contributions to the study of the important reactions...