Assessing Conceptual Understanding and Misconceptions of the Periodic Table among Grade 10 Learners: A Diagnostic Approach

This study aimed to investigate the learning gaps and misconceptions of Grade 10 students regarding the Periodic Table of Elements through a systematically developed and validated diagnostic assessment instrument. Employing a descriptive research design, an initial 50-item test was content-validated by three experts and pilottested with 150 students. Item analysis and reliability assessment using Cronbach’s alpha resulted in a finalized 36-item diagnostic tool, which was subsequently administered to 100 Grade 10 students from selected public secondary schools in the hinterland areas of Iligan City. Data were analyzed using mean scores and percentage distributions to identify learning gaps and patterns of incorrect responses. Findings revealed persistent misconceptions in foundational concepts, including atomic structure, differentiation between atomic number and mass number, historical development of the Periodic Table, and periodic trends such as atomic radius, ionization energy, and electronegativity. Many learners demonstrated difficulty explaining these trends in terms of underlying principles, including effective nuclear charge and electron shielding. These results underscore the need for targeted instructional interventions that address misconceptions and foster deeper conceptual understanding of the Periodic Table. The validated diagnostic tool provides a robust foundation for designing remedial strategies and enhancing chemistry instruction at the secondary school level.