Understanding Quantum Numbers in General Chemistry Textbooks

Abstract

Quantum numbers and electron configurations form an important part of the general chemistry curriculum and textbooks. The objectives of this study are: (1) Elaboration of a framework based on the following aspects: (a) Origin of the quantum hypothesis, (b) Alternative interpretations of quantum mechanics, (c) Differentiation between an orbital and electron density, (d) Differentiation and comparison between classical and quantum mechanics, and (e) Introduction of quantum numbers based on electron density; (2) Formulation of five criteria based on the different aspects (a, b, c, d, and e), and (3) Evaluation of 55 freshman college‐level general chemistry textbooks. Results obtained show: Criterion 1, none of the textbooks described satisfactorily that Planck’s role in the origin of the quantum hypothesis was more at the level of an empirical adjustment, whereas Einstein provided the physical significance of the quantum hypothesis; Criterion 2, few textbooks (two satisfactory and four mentioned) included alternative interpretations of quantum mechanics (e.g., Bohm) and thus ignored that most theories are underdetermined by experimental evidence; Criterion 3, none of the textbooks described satisfactorily that orbitals are mathematical constructs and the shapes of the orbitals (s, p, d, f) are not derived from quantum mechanics but instead from electron density measurements; Criterion 4, although, quantum mechanics approaches classical mechanics as a limiting case, none of the textbooks presented a framework to facilitate transition in student understanding from classical to quantum mechanics (28 textbooks made a simple mention); and Criterion 5, few textbooks (one satisfactory, five mentioned) facilitated the introduction of quantum numbers based on experimental determination of electron density (photoelectron spectrum). It is concluded that the inclusion of these criteria in textbooks can facilitate students’ conceptual understanding of quantum numbers and electron configurations.