Ionic bonds students’ misconceptions

Ions in Precipitation Reactions. Grade 10 students of German academic high schools have learnt the atomic model and about the idea of the ion and ionic bonding in their chemistry lessons. These students saw precipitates of calcium sulfate from saturated salt solutions and have been asked to imagine the smallest particles in these solutions before and after the precipitation [6]. The expected ion symbols of the initial solution were correctly supplied in 50% of the cases. However, the other half of the student group has shown misconceptions of salt molecules or of electron transition in the formation of ions from atoms . With respect to the precipitation product, only 30% of the students provided acceptable structural models, the amount of misconceptions grew to 70% [6]. 

Fig. 5.15 Empirical findings towards student s misconceptions of ionic bonding [13]...

The conversation shows that the teacher does not clarify the student s position and the misconception is thereby produced or even cemented by the lecture. The student thinks therefore that the electric conductivity of a solution confirms an ionic bonding, whereas for the teacher, it confirms the existence of free moveable ions in the solution. This leads to the student not being able to differentiate between ions and ionic bonding, that students think the conductivity of a solution is equal to that of an ionic bonding they are not capable of separating ionic bonding from the existence of free moving ions. 

It is further indicated that misconceptions are mainly because the terms electron transfer and ionic bonding are set equal in chemistry lessons. Students concern themselves only with isolated ions instead of with giant structures. They substantiate the number of bonds that an ion can form, with isolated bonds between individual ions they reinforce their ideas additionally with the Octet rule and the resulting noble gas configuration of individual ions. 

Ion Pairs and Molecules. Students show basic misconceptions regarding ionic bonding even if they are confronted with a correct two-dimensional model of an ionic lattice (see Fig. 5.17) - because they are mostly thinking of ion pairs [15] one positive and one negative ion are connected through ionic... 

Based on the above-mentioned students misconceptions that the ions always arrange in pairs or molecules, it seems understandable that students also have huge problems conceiving the arrangements of ions. The works of Butts and Smith [20] show great deficits of students in spatial images of ionic bonds. They note that most students have a concept of the two-dimensional formation of crystal lattices Only four students demonstrated a clear and accurate... 

Animistic Concepts of Ions. From the literature, the animistic idea of ions, i.e. their personification, has been named as animistic misconception. This can be equated with the anthropomorphic language with which the wishes or preferences of ions are described. As an example, students state that electrons belong to certain atoms, or they formulate their statements regarding two atoms in such a way that an atom wants to form a bond, or an atom would like to receive an electron because it wishes to have a full outer shell. Taber continues with atoms - according to students - like to be stable, wish to be stable, prefer to be stable and indeed can be very eager to be stable [17]. Various scientists in relation to both ionic formation and ionic bonding [16,22,23], have also found such an animistic language used by students. 

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