Which type of reactions involve the transfer of electrons between elements?

Redox reactions, or reduction-oxidation reactions, are characterized by the transfer of electrons between elements. In these reactions, one species undergoes oxidation, losing electrons, while another species undergoes reduction, gaining those electrons. This transfer is fundamental because it changes the oxidation states of the involved atoms and is essential in various chemical and biological processes, including cellular respiration and combustion.

In contexts such as combustion reactions, while they do involve electron transfer, they are more specifically associated with the reaction of a substance with oxygen to produce heat and light, which may not highlight the electron transfer aspect as clearly as redox reactions do. Decomposition and synthesis reactions also don’t primarily focus on electron transfer; instead, they involve breaking down a compound into simpler products or combining elements or simpler compounds to form a more complex compound, respectively. Therefore, redox reactions uniquely encompass the concept of electron transfer, distinguishing them from the other types of reactions listed.