This learning resource focuses on the atomic structure and valence electrons of key elements: Hydrogen, Carbon, and Sodium. It guides students through a comprehensive analysis of subatomic particles, using a review format for protons, neutrons, and electrons, along with their respective charges and locations. Students will retrieve information from the periodic table, sketch Bohr models to depict electron arrangements, and identify the number of valence electrons for each element. The resource also includes a reflective component where students assess their confidence regarding their understanding of valence electrons. Finally, it examines the relationship between valence electrons and atomic reactivity, encouraging students to explore why certain atoms behave differently based on their electron configurations.