Oxygen is the 8th Element of the Periodic Table. At the atmospheric pressure and temperature of the Earth it is in the form of a colourless, odourless dimeric gas, O2, and makes up around 21% of the atmosphere. Atomically, oxygen contains 8 protons, 8 neutrons and 8 electrons when not in the form of an Isotope. It has a melting point of 54.36 K and a boiling point of 90.20 K.
Oxygen plays an important role in the biological process of Respiration where it is used as a substrate in combination with Glucose to produce Carbon Dioxide and Water. It is also produced in the process of photosynthesis, where carbon dioxide and water are involved in the presence of light energy to form oxygen and glucose.
- ↑ Essential Cell Biology, Bruce et al. 3rd ed 2009, New York p488-9