8O Oxygen

Year Discovered


Discovered By

Joseph Priestley of England and Karl Scheele of Sweden

Biological Rating

Necessary for all life.


Named from the Greek words meaning “acid forming”, oxygen is a colorless and odorless gas. It is the third most common element in the universe. It is very reactive and will readily react with all other elements, except for the lightest noble gases (He, Ne, Ar, and Kr). In addition to being the most common element in the Earth’s crust, it makes up 21 % of the atmosphere. Due to its reactivity, oxygen is used in a wide variety of chemical production and applications. Oxygen is also used in steel-making, metal-cutting and in medical treatment.

Biological Benefits

Oxygen probably deserves the title of most important element for most types of life. It is one of the six bulk elements and it is the most common element in the human body, making up 61 % of the average human’s mass. In addition to being a constituent of DNA, it is also plays a role in most other biological compounds. It is used in the respiration of most organisms. Last but not least, it is a component of water, upon which all life depends.

Role in Life Processes

Percentage Amount in the Human Body: 61.43%


Oxygen is chiefly obtained by liquefying air. Oxygen is the most common element on the surface of the Earth, occurring as oxygen gas, in water, and oxide minerals, or in combination with elements in silicates, carbonates, phosphates, sulfates, and many others.