Conceptual Chemistry

In a recent contribution to ChemEd X "Stoichiometry is Easy", the author states that he has "vacillated over the years between using an algorithmic method, and an inquiry-based approach to teaching stoichiometry. " I would like to suggest that there is another approach to mastering stoichiometry and that it should precede the algorithmic one: it is the conceptual approach based on a particle model to represent the species involved in chemical reactions.