Oxidation and Reduction

We saw in the main part of this story that, when the blue-green bacteria began to release oxygen by the process of photosynthesis, iron began to rust and many bacteria died. This process of oxygen gaining an electron when combining with other atoms is called oxidation.

It is interesting to note that at the same time as the oxygen gains an electron, the iron loses an electron. This is called the reduction of iron.

An atom which can easily lose an electron, such as iron or hydrogen, is called a reducing agent. When oxygen combines with hydrogen to make water, the oxygen gains an electron from the hydrogen. The hydrogen is oxidized and the oxygen is reduced.

Oxidation and reduction are one of the fundamental processes in chemistry.

An atom which can lose electrons is called a reducing agent or electron donor. Hydrogen and iron are reducing agents.