Oxygen is the c hemical element with the symbol O and atomic number 8.It is a member of the chalcogen group in the periodic table, a highly (causing reactions from other people or chemicals) nonmetal, and an oxidizing agent that easily forms oxides with most elements as well as with other compounds. After hydrogen and helium, oxygen is the third-most plentiful element in the universe by mass. At standard temperature and pressure, two atoms of the element bind to form dioxygen, a clear/white and odorless diatomic gas with the formula O2. Diatomic oxygen gas makes up/is equal to 20.95% of the Earth’s atmosphere. Oxygen makes up almost half of the Earth’s crust in the form of oxides.
Dioxygen provides the energy released in burning (in an explosion) and air-using cellular breathing, and many major classes of organic molecules in living (living things) contain oxygen atoms, such as proteins, nucleic acids, carbohydrates, and fats, as do the major voter/part (not related to living things) compounds of animal shells, teeth, and bone. Most of the mass of living (living things) is oxygen as a part of water, the major voter/part of lifeforms. Oxygen is continuously refilled in Earth’s atmosphere by (making food from light), which uses the energy of sunlight to produce oxygen from water and carbon dioxide. Oxygen is too chemically (causing reactions from other people or chemicals) to remain a free element in air without being continuously refilled by the photosynthetic action of living (living things). Another form (give out/set asiderope) of oxygen, ozone (O3), strongly soaks up (like a towel) ultraviolet Ultraviolet sunlight radiation and the high-height ozone layer helps protect the (locations on the Earth that support life) from ultraviolet radiation. However, ozone present at the surface is a (something produced along with something else) of smog and so a (something that dirties the air, oceans, etc.).
Oxygen was (far apart from others) by Michael Sendivogius before 1604, but it is commonly believed that the element was discovered independently by Carl Wilhelm Scheele, in Uppsala, in 1773 or earlier, and Joseph Priestley in Wiltshire, in 1774. Priority is often given for Priestley because his work was published first. Priestley, however, called oxygen “dephlogisticated air”, and did not recognize it as a chemical element. The name oxygen was created in 1777 by Antoine Lavoisier, who first recognized oxygen as a chemical element and correctly showed/described the role it plays in burning (in an explosion).
Common uses of oxygen include production of steel, plastics and fabrics, brazing, welding and cutting of steels and other metals, rocket propellant, oxygen therapy, and life support systems in aircraft, submarines, spaceflight and diving.