Subscribe to our newsletter. Except for a few anaerobic organisms, oxygen is needed by all life on earth. Oxyhemoglobin Dissociation Curve Oxygen, the eighth element on the Periodic Table , with an atomic weight of 16.
Oxygen exists as a gas at room temperature in the form of a diatomic molecule.
This means it's usual state is a molecule consisting of two atoms of oxygen. As a gas it is colorless, but as a liquid it has a pale blue tint. Except for some microscopic anaerobic organisms, all life on earth depends on air and the oxygen it contains. Our lungs are the organs that make it possible for the oxygen in the air to get into our blood stream and then the rest of the body. Diseases of the lungs impair this ability and we use oxygen in more purified forms to help treat the symptoms caused by these diseases.