The study explores chunking strategies applied in Short Term Memory (STM) by upper secondary students of mixed chemistry learning abilities. The aim of the study is to observe variations in chunking strategies utilized by these students when learning the Periodic Table of Elements in the Form Four Chemistry syllabus. Findings show that students applied varied chunking strategies, of which, three patterns prevailed at STM level: similar chunking, mixed chunking, and characteristic chunking. Secondary school teachers in guiding their students through the Chemistry learning process should remain mindful of presenting didactic materials in a way that not only accommodates the students' various chunking strategies abilities needs, but at the same time hone the students' learning skills.