An alternative program of instruction was implemented with 33 high-achieving Grade 9 students (15-16 years old) in Singapore that overtly focused on the use of macroscopic, submicroscopic, and symbolic representations to describe and explain the changes that occurred during the burning of metals, reactions of dilute acids, ionic precipitations, and metal ion displacement reactions. Students' understandings of the use of multiple levels of representation were evaluated at the end of nine months of instruction using a previously developed 15-item, two-tier, multiple-choice diagnostic instrument. In several instances the students displayed much better understanding of the three systems of representation than 44 students from another higher-achieving Grade 9 class who were taught with the regular instructional program that did not emphasize use of multiple levels of representation. Comparison of the mean diagnostic test scores of students from the two classes indicated that the high-achieving class in the treatment group that experienced the alternative program of instruction performed significantly better than the higher-achieving class from the comparison group that experienced the regular program of instruction, further validating the efficacy of the alternative instructional program. (Contains 1 table and 1 figure.)