How does reduction differ from oxidation in a chemical reaction?

In a chemical reaction, oxidation and reduction are coupled processes that involve the transfer of electrons.

Oxidation is defined as a process where an atom, ion, or molecule loses electrons, increasing its oxidation number. This can occur through the loss of electron density, often when a carbon atom bonds to a more electronegative atom like oxygen, or when hydrogen atoms are removed from carbon.123

Reduction, conversely, is a process where an atom, ion, or molecule gains electrons, decreasing its oxidation number. This happens when a substance reduces a chemical compound, typically by donating electrons. Common reduction reactions involve the addition of hydrogen to a carbon atom or the removal of oxygen from a carbon atom.4253

These two processes always occur together; an oxidation reaction is always accompanied by a reciprocal reduction reaction. For example, when magnesium burns in oxygen, magnesium is oxidized as it gives up electrons, and oxygen is reduced as it accepts them.67