A reaction involving the transfer of an electron between atoms with a slight difference in electronegativity can still be classified as a redox reaction, as redox reactions are defined by changes in oxidation states of the species involved. To clarify any uncertainties regarding a specific reaction, it is recommended to write the balanced chemical equation and assign oxidation numbers. Ultimately, the classification of a reaction as redox may depend on personal interpretation, but the fundamental principles of oxidation state changes remain central to the definition.
