IP Chemistry Upper Sec 02: Particulate Nature of Matter

These notes align with SEAB GCE O-Level Chemistry (6092) content used in IP programmes (exams from 2026).

Status: SEAB O-Level Chemistry 6092 syllabus (exams from 2026) checked 2025-11-30 - scope unchanged; remains the reference for this note.

What you must know

• Kinetic particle theory: solids (closely packed, vibrate), liquids (close but slide), gases (far apart, rapid and random). Energy changes drive melting/boiling/condensation/freezing.
• Diffusion: particles spread from high to low concentration; faster at higher temperature and for lighter molecules (e.g., H₂ vs CO₂).
• Atomic structure: protons (+1, mass 1), neutrons (0, mass 1), electrons (−1, mass ~1/1836); proton number = electrons in atom; nucleon number = p + n.
• Nuclide notation and isotopes: $\ce{^{A}_{Z}X}$