How does the transfer of electrons occur in redox reactions?

In redox reactions, electrons are transferred from one atom (the reducing agent) to another atom (the oxidising agent).

In a redox reaction, there is always a transfer of electrons from one species to another. This process involves two simultaneous reactions: oxidation and reduction. Oxidation is the loss of electrons, while reduction is the gain of electrons. The substance that loses electrons is called the reducing agent, and the substance that gains electrons is called the oxidising agent.

Let's take an example of a simple redox reaction: the reaction between magnesium and oxygen to form magnesium oxide. In this reaction, magnesium (Mg) loses two electrons to become Mg2+, undergoing oxidation. These electrons are then gained by oxygen (O2), which is reduced to form O2-. The magnesium has acted as the reducing agent, and the oxygen as the oxidising agent.

The transfer of electrons in redox reactions is fundamental to many chemical processes, including combustion, respiration, photosynthesis, and the operation of batteries. In all these processes, energy is often released, which can be harnessed for various purposes.

It's important to note that the number of electrons lost in the oxidation half-reaction must equal the number of electrons gained in the reduction half-reaction. This ensures that the overall charge is conserved in the reaction. This is why redox reactions are often balanced in terms of both mass and charge.

In summary, the transfer of electrons in redox reactions involves one species losing electrons (and being oxidised) and another species gaining those electrons (and being reduced). This transfer is facilitated by the reducing and oxidising agents, and is crucial to many chemical and biological processes.