Two Ideas of the Redox Reaction: Misconceptions and their Challenge in Chemistry Education

In interpretations of chemical phenomena students like to mix the macro level of substances with the sub-micro level of atoms, ions and molecules: “water boils at 100 oC and has an angle” – instead of separating properties of substances (water has a special density, freezing and boiling point) and properties of particles (the H2O molecule has an angle, H and O atoms are linked by electron-pair bond). For redox reactions students are doing this too: “one Cu2+ ion takes two electrons and is reduced to copper” – instead of “to one Cu atom”! Another difficulty seems to be the historical redox definition with the “oxygen transfer”: this idea is so attractive that students argue mostly with oxygen participation instead of the transfer of electrons. This article reflects those misconceptions and proposes ways of instruction to prevent from “schoolmade misconceptions”.