What is the oxidation number and how does it relate to redox reactions?

The oxidation number is the charge an atom would have if all its bonds were 100% ionic. It is crucial in redox reactions as it indicates the transfer of electrons from one species to another.

In simple terms, oxidation number is the number of electrons an atom gains or loses when it forms a compound. The oxidation number of an atom in a molecule or ion is assigned based on a set of rules. For example, the oxidation number of an element in its elemental state is always zero, while the oxidation number of oxygen is usually -2 in compounds.

Redox reactions involve the transfer of electrons from one species to another. The species that loses electrons is said to be oxidized, while the species that gains electrons is said to be reduced. The oxidation number of an atom changes during a redox reaction, indicating the transfer of electrons.

For example, in the reaction between zinc and copper sulfate, zinc is oxidized to zinc ions with a +2 oxidation number, while copper ions are reduced to copper atoms with a 0 oxidation number. The change in oxidation number of zinc from 0 to +2 indicates the loss of two electrons, while the change in oxidation number of copper from +2 to 0 indicates the gain of two electrons.

In conclusion, the oxidation number is a crucial concept in redox reactions as it indicates the transfer of electrons from one species to another. Understanding oxidation numbers is essential in predicting the outcome of redox reactions and balancing chemical equations.