Establishes core understanding of matter and chemical change through NGSS HS-PS–aligned ideas and practices. Emphasizes safe laboratory technique, measurement with significant figures and dimensional analysis, and evidence-based reasoning. Covers properties and classification of matter; atomic structure, isotopes, and electron configuration; periodic organization and trends; ionic, covalent, and metallic bonding plus intermolecular forces; and nomenclature and formula writing. Develops stoichiometry (mole concept, molar mass, balanced equations, percent yield), reaction types and prediction, states of matter, gas laws, and kinetic molecular theory, thermochemistry and calorimetry, solutions and molarity, introductory acids–bases, kinetics and equilibrium, and a survey of nuclear chemistry.