ASSESSING THE STUDENTS’ UNDERSTANDING RELATED TO MOLECULAR GEOMETRY USING A TWO-TIER DIAGNOSTIC TEST

In this research, the comprehension levels and misconceptions of university students on the subject of molecular geometry were determined via a two-tier diagnostic test consisting of 25 items developed by researchers. It was applied on 110 university students. The reliability and validity tests and item analyses were conducted in relation to the test, and the difficulty and discrimination indices of the items were detected. The reliability coefficient of the test was found to be 0.856 while the mean difficulty value of the test was 0.487. According to the findings obtained from the second tier of the test containing open end questions, the students had a great deal of wrong information and numerous misconceptions in relation to the molecular geometry. Such statements as “atoms move in the resonance structure” and “bond angles of two molecules having a trigonal pyramidal shape cannot be different” are counted among the most important misconceptions determined in the study.