Teaching and learning the concept of chemical bonding.

Chemical bonding is one of the key and basic concepts in chemistry. The learning of many of the concepts taught in chemistry, in both secondary schools as well as in the colleges, is dependent upon understanding fundamental ideas related to chemical bonding. Nevertheless, the concept is perceived by teachers, as well as by learners, as difficult, with teaching commonly leading to students developing misconceptions. Many of these misconceptions result from over-simplified models used in text books, by the use of traditional pedagogy that presents a rather limited and sometimes incorrect picture of the issues related to chemical bonding and by assessments of students' achievement that influence the way the topic is taught. In addition, there are discrepancies between scientists regarding key definitions in the topic and the most appropriate models to teach it. In particular, teaching models that are intended to have transitional epistemological value in introducing abstract ideas are often instead understood by students as accounts of ontological reality. In this review paper we provide science educators, curricula developers and pre-service and in-service professional development providers an up-to-date picture regarding research and developments in teaching about chemical bonding. We review the external and internal variables that might lead to misconceptions and the problematic issue of using limited teaching/learning models. Finally, we review the approaches to teaching the concept that might overcome some of these misconceptions. [ABSTRACT FROM AUTHOR]