Linking Conceptual Understanding and Competency Mastery in Senior High School Chemistry: A Diagnostic Study

This study investigated the conceptual understanding and mastery of key chemistry competencies among Grade 11 STEM learners at Pangutaran National High School. Using a descriptive quantitative research design, a diagnostic assessment aligned with the Senior High School Most Essential Learning Competencies (MELCs) was administered to fifty purposively selected participants. The assessment evaluated learners’ proficiency across ten chemistry competencies, including stoichiometry, gas laws, chemical equilibrium, chemical reactions, and chemical representations. Results indicated that the majority of learners exhibited low conceptual understanding, with only one competency classified as mastered, two as nearly mastered, and two as not mastered, corresponding to the least mastered competencies. The highest-performing competency involved representing compounds using chemical formulas and structures (84%), whereas the lowest-performing competency was calculating empirical formulas from percent composition (38%). The overall mean score of 62.07% fell within the least mastered classification, highlighting widespread difficulties in integrating mathematical reasoning, conceptual interpretation, and symbolic representation. These findings are consistent with prior research indicating that learners tend to perform better in representational tasks while struggling with quantitative and abstract concepts. The study underscores the need for conceptually oriented instruction, targeted remediation strategies, and the integration of diagnostic assessment feedback to enhance chemistry learning outcomes and address persistent misconceptions.