oksigeen

Oksigeen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table. Oxygen is a highly reactive nonmetal and an oxidizing agent that readily forms oxides with most elements. Its atomic mass is approximately 15.999 atomic mass units.

In its elemental form, oxygen exists as a diatomic molecule, O₂, which is a colorless, odorless gas at standard temperature and pressure. This diatomic oxygen makes up about 20.95% of Earth's atmosphere. Ozone, a molecule with three oxygen atoms (O₃), is an important component of the stratosphere and plays a crucial role in absorbing ultraviolet (UV) radiation from the sun.

Oxygen is essential for aerobic respiration, the process by which most living organisms, including humans, extract energy from food. It is also a key component of water (H₂O) and many organic molecules, making it fundamental to life as we know it.

Industrially, oxygen is produced through the cryogenic distillation of air or by electrolysis of water. It has numerous applications, including in medicine for respiratory therapy, in welding and cutting metals, and as an oxidizer in rocket propulsion.