- Chemical bonding in general is a topic that lot of children struggle with and they often have a wrong conceptual understanding. - This paper has created and used a diagnostic instrument to evaluate students understanding of chemical bonding. The main difference with their instrument and normal assessment methods is that they ask multiple choice questions in two parts. The first part is the answer to the question and the second asks for the reason why the student provided the answer. - The paper proposes that such a method is much more effective to find gaps in students' understanding. They find simply getting the answer doesn't reveal much. ---- Tan, Kim Chwee Daniel, and David F Treagust. "Evaluating students’ understanding of chemical bonding." (1999). - [Link](https://citeseerx.ist.psu.edu/document?repid=rep1&type=pdf&doi=c8cf41fac4d590d0c690acee5711f649c2856d2a)