Abstract
The paper is aimed at defining reduction, oxidation, and redox reactions based both on the oxidation number and charge changes in reacting species. It is rationalized that the processes of oxidation and reduction, usually occurring simultaneously, can occur also as independent processes. It is explained that in balancing chemical equations of redox reactions the “gain” or “loss” of electrons should be understood as changes in oxidation number. A formal expressions “+n e−” and “−n e−” represent in reality a decrease and increase in oxidation number by n units, respectively