The general chemistry curriculum includes a prelude that consumes nearly all of the first semester and occupies the first third of the typical textbook. This necessary prelude to the main event is comparable in scope to precalculus though not broken out as a formal ‘prechemistry’ course. Atomic orbitals account for much of this prelude-to-chemistry. By tradition, orbital theory is conveyed to the student in three disjunct pieces, presented in the following illogical order: the Pauli principle, the Aufbau principle, and (...) Hund’s rule. (Often the n + l rule is tossed into the mix as well, though with no fixed place in the scheme). In the early twentieth century, as various researchers announced new insights into the atom at unpredictable intervals, no one could have been faulted for teaching orbitals in such a manner, catch-as-catch-can. A hundred years on, the vestiges of that (presumed) practice look wrong, and are indefensible. In the approach advocated here, orbitals would be taught as a single hierarchical rule-set, with the parts coherently sequenced as Aufbau–Hund–Pauli (and with Madelung’s n + l rule rehabilitated as part of Aufbau, no longer a free-floating mnemonic aid only). Logic aside, pragmatism offers its own argument for adopting this scheme: A tighter approach to Aufbau can lighten the ‘prechemistry’ burden significantly and bring the student that much sooner to chemistry itself. (shrink)

This article describes a descriptive-qualitative method for analyzing and reviewing several textbooks for high school as samples commonly used by teachers and students in their teaching–learning to reveal possible misconceptions. This study focused on the subjects of quantum numbers and electronic configuration. From the advanced literature review to analyze the samples the occurrence of various misconceptions was noted. All textbooks described correctly the four symbols of quantum numbers, but none correlates correctly the magnetic-angular quantum number to the Cartesian labeled orbitals. (...) All textbooks consider mistakenly the meaning of aufbau as the building-up energy of orbitals by following (n + ℓ, n) rules on describing the electronic configuration for all atoms. Only one textbook states that the electronic configuration of transition metal atoms (3d series) can be described in the following order of shell (n), thus giving rise to two types of electronic configurations, [Ar] 3d 4s (Type I) beside [Ar] 4s 3d (Type II), leading further misconception. All textbooks described favorably an unpaired electron of ms = + ½ due to the specific agreement, which is a potential misconception in applying Hund’s rule. In drawing the diagram boxes of orbitals, they are arranged in increasing or decreasing the numeric mℓ, due to the specific agreement, and again leading to a potential misconception on describing the quantum number of electrons issued. Three textbooks introduced the terms of the last and the xth electron associated with the quantum numbers, leading to serious further misconceptions. No books stated that the ordering energy of the (n + ℓ, n) rule is true only for the first twenty atoms. (shrink)