Students’ misconceptions redox reactions

In Chap. 8, redox reactions and the transfer of electrons will be discussed and in Chap. 9, complex reactions and the transfer of ligands will be presented. For all these essential concepts, questions will be raised related to students misconceptions. Finally strategies for teaching and learning to prevent or cure these preconceptions and school-made misconceptions will be discussed. 

School-made misconceptions play a more significant role by advanced students, they do not differentiate between atoms and ions, atoms and substances, or substances and particles they are simply used as synonyms. Several students do not seem to be aware that redox reactions between atoms and ions are necessary to explain the formation of elemental copper in their mind copper sulfate solution already contains the copper atoms copper from copper sulfate forms a deposit on the iron nail, it connects to the iron atoms . Students definitely lack an understanding of the concept of ions in salt solutions (see Chap. 5). 

The reason for the low number of correct answers mostly lies in the misconception that the mere presence of acids automatically leads to an acid-base reaction. Even when a student has understood the redox reaction and has supplied a plausible explanation, misconceptions still remain, as is shown in the following example Cu is nobler and is therefore reduced, it accepts electrons and Mg is oxidized because the active metal releases electrons, the voltage is created through ion formation . 

Summary. It is pointed out that, in order to avoid misconceptions, the introduction of ions is very important ions have been dealt with as basic particles of matter according to Dalton s atomic model (see Chap. 5). In order to understand the charges of ions and the change of ions and atoms by electron transfer, the differentiated atomic model with nucleus and electron shells should be introduced. With the assistance of a clear terminology, it is easy to formulate half-reaction for the oxidation and reduction steps, the number of electrons to be transferred can be clearly recognized. Finally, if mental models -for instance, from involved atoms or ions in Galvanic cells or in batteries - are relayed and drawn by the students themselves, then they could more easily see through the redox processes or even perhaps be able to repeat them independently. In all explanations, one should pay attention that the observations should be done at the substance level, but that the interpretations and discussions of reaction equations should consequently take place at the level of the smallest particles as atoms, ions and molecules. 

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