AP Chemistry Notes — All 9 Units

AP Chemistry is one of the most demanding AP courses — the 9 units build on each other, and the FRQ section requires you to explain phenomena at the molecular level, not just calculate. These notes hit the key concepts and the reasoning patterns the exam rewards.

Unit 1: Atomic Structure and Properties

Electron configuration (aufbau, Pauli exclusion, Hund's rule), periodic trends (atomic radius, ionization energy, electronegativity, electron affinity), photoelectron spectroscopy (PES) for identifying elements from ionization energy peaks.

Unit 2: Molecular and Ionic Compound Structure and Properties

Lewis structures, VSEPR (electron domain geometry vs. molecular geometry), polarity (bond dipoles + molecular shape), ionic bonding vs. covalent bonding, formal charge, resonance structures.

Unit 3: Intermolecular Forces and Properties

Types of IMFs in order of strength: London dispersion (all molecules) < dipole-dipole < hydrogen bonding. How IMF strength predicts boiling point, vapor pressure, viscosity, surface tension. Solubility (like dissolves like). Colligative properties (boiling point elevation, freezing point depression, osmotic pressure).

Unit 4: Chemical Reactions

Balancing equations, net ionic equations, classifying reactions (synthesis, decomposition, single/double displacement, combustion, acid-base, redox). Stoichiometry: molar mass, mole ratios, limiting reagent, percent yield.

Units 5–6: Kinetics and Thermodynamics

Rate laws (rate = k[A]ⁿ[B]ᵐ), integrated rate laws (zero/first/second order), half-life, Arrhenius equation (k = Ae^(-Ea/RT)). Enthalpy (ΔH), Hess's Law, calorimetry. Entropy (ΔS) and Gibbs free energy (ΔG = ΔH − TΔS): ΔG < 0 → spontaneous.

Units 7–8: Equilibrium and Acids/Bases

Equilibrium expression K, reaction quotient Q, Le Chatelier's principle. Ka and Kb, pH calculations (strong vs. weak acids/bases), buffer solutions (Henderson-Hasselbalch), titration curves.

Unit 9: Electrochemistry

Galvanic vs. electrolytic cells, standard reduction potentials (E°cell = E°cathode − E°anode), Faraday's law, Nernst equation.

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