Provide an example of the oxidation number of different elements in redox reactions.

An example of the oxidation number of different elements in redox reactions is the reaction between magnesium and oxygen.

When magnesium reacts with oxygen, it undergoes oxidation, while oxygen undergoes reduction. Magnesium loses two electrons to form Mg2+ ions, which have an oxidation number of +2. Oxygen gains two electrons to form O2- ions, which have an oxidation number of -2.

The oxidation number of an element is a measure of the number of electrons it has gained or lost in a chemical reaction. In a redox reaction, one element undergoes oxidation (loses electrons) while another undergoes reduction (gains electrons).

In the case of the reaction between magnesium and oxygen, magnesium is oxidised because it loses electrons, while oxygen is reduced because it gains electrons. The oxidation number of magnesium increases from 0 to +2, while the oxidation number of oxygen decreases from 0 to -2.

Overall, the reaction between magnesium and oxygen can be represented as:

2Mg + O2 → 2MgO

In this reaction, magnesium is oxidised and oxygen is reduced, and the oxidation numbers of the elements change accordingly.