The central goal of this study was to examine the extent to which a teaching approach focused on the interaction between macroscopic, submicroscopic, and symbolic levels of chemistry representations could affect high school students' performance in the field of inorganic reactions, as well as to examine how the applied instruction influences students' assessment of invested mental effort. The total sample of this research included 313 high school students. The survey was conducted during the 2012-2013 school year. As a measuring instrument for student performance, a two-tier multiple-choice test of knowledge was used. Each task in the test was followed by a seven-point Likert-type scale for evaluation of invested mental effort. Our findings indicate that a teaching strategy relying on the interplay between three levels of knowledge representation leads to an increase in students' performance and also contributes to the reduction of cognitive load. The obtained results for calculated mental efficiency suggest that the applied instructional model represents an effective teaching model.