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Oxidation and reduction

A bonfire, an example of oxidation Lighting a fire, iron rusting and even our own breathing are all examples of a kind of chemical reaction called oxidation. Substances that gain oxygen or lose hydrogen atoms are said to be oxidized, while those that lose oxygen or gain hydrogen atoms are said to be reduced. Both always happen at the same time and are called "redox" reactions, a mixture of the two words "reduction" and "oxidation".



Sodium and fluorine bond to form sodium fluoride—an example of a redox reaction. Sodium loses its outer electron to give it a...Read More >>Sodium and fluorine bond to form sodium fluoride—an example of a redox reaction. Sodium loses its outer electron to give it a stable structure, and this electron is gained by the fluorine atom. The sodium is oxidized while the fluorine is reduced.

Electron transfer 

Both oxidation and reduction always involve the movement of electrons from one atom to another. During oxidation, an atom loses electrons; during reduction an atom gains them. In fact, oxidation describes all chemical reactions in which electrons are lost, whether or not oxygen is involved.
A rusting old car. The iron in its body combines with oxygen in water in a chemical reaction to produce iron oxide—rust.

Reactions with oxygen

The term oxidation was first used by the French scientist Antoine Lavoisier (1743–94) to mean a reaction of a substance with oxygen. When later scientists understood that the atoms of a substance being oxidized were losing electrons, the term oxidation came to include all other chemical reactions in which electrons are lost, whether or not oxygen was involved.

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