Oxidation is a process where a substance loses electrons, while reduction is a process where a substance gains electrons.
Together, oxidation and reduction are called redox reactions.
Oxidation and reduction always occur together because when one substance loses electrons, another substance must gain those electrons.
In redox reactions, the substance that loses electrons is called the reducing agent, while the substance that gains electrons is called the oxidizing agent.
An oxidizing agent causes oxidation, while a reducing agent causes reduction.
The oxidation state of an atom in a molecule or ion describes how many electrons that atom has gained or lost compared to its neutral state.
In a redox reaction, the total number of electrons lost by the reducing agent must equal the total number of electrons gained by the oxidizing agent.
In many cases, redox reactions involve the transfer of hydrogen ions (H+) along with electrons.
Redox reactions are important in many biological processes, including respiration and photosynthesis.
Corrosion is an example of a redox reaction where metal is oxidized by oxygen in the air, forming metal oxides.
