Abstract
A simple educational tool was prepared and practiced for learning electronic configuration of atoms and molecules. This tool consisted of an A4 size sheet for the simulation of electronic configuration of an atom on the front side, and that of a molecule on the back side, and sixteen round counting chips (19 mm o.d.) indicating electron spin (s) of a lone and paired electron (s) on the front and back side. This tool was possible to simulate the ground state electron configuration of atoms from hydrogen to zinc, and of homonuclear diatomic molecules from hydrogen to neon on the periodic table. It was inferred that the tool was useful for understanding and explaining these electronic configurations from the results of questionnaires for the first-year students.
