QUANTUM-CHEMICAL CONCEPTS: ARE THEY SUITABLE FOR SECONDARY STUDENTS?

Abstract

Quantum-chemical theories of atomic and molecular structure are now part of the upper secondary curriculum in many countries, despite the fact that many educators are against their use in basic chemistry courses. In this paper, we first summarise the main findings of previous work on chemistry students’ knowledge and understanding of atomic orbitals, molecular orbitals and related concepts. We then report results of a study with twelfth-grade Greek students. A test was used that required critical thinking, and aimed to find whether students had acquired a deep understanding of the relevant concepts. The findings indicate that such understanding was missing from most students. Students did not have a clear understanding of orbitals, and especially their probabilistic rather than deterministic nature; for many, the orbitals represent a definite, well-bounded space; they did not realise the approximate nature of atomic orbitals for many-electron atoms; the inadequacy of the carbon-atom, ground-state, electron configuration to account for its valency of four was not evident. Implications for instruction and the curricula are discussed. [Chem. Educ. Res. Pract. Eur.: 2002, 3, 129-144]