AP Chemistry Ultimate Guide

Unit 1: Atomic Structure and Properties

The Periodic Table

• Element Basics:
  • Example: Carbon (C)
  • Atomic Number: Tells you number of protons/electrons in neutral atom
  • Molar Mass: Average mass of atom/mole in amus/grams
• Table Organization:
  • Horizontal rows: Periods
  • Vertical columns: Groups
  • Groups include Alkali Metals, Alkaline Earth Metals, Transition Metals, Halogens, Noble Gases
• Atom Identity: Determined by proton count in nucleus
• Isotopes: Atoms with different neutron counts
• Mass Spectrometry: Determines mass of isotopes

Moles

• Avogadro's Number: 6.022x10^23 particles/mole
• Conversions:
  • Moles to grams using atomic mass
  • Moles to gas volume using ideal gas law
• Molarity: Concentration of a solution

Electron Configurations and the Periodic Table

• Coulomb's Law: Attraction force between charges
• Bohr Model: Energy levels and electron transitions
• Photoelectron Spectroscopy: Measures ionization energies
• Periodic Trends: Atomic radius, ionization energy, electronegativity

Unit 2: Molecular and Ionic Compound Structure and Properties

Bonds Overview

• Ionic Bonds: Electrostatic attraction between metals and nonmetals
• Metallic Bonds: "Sea of electrons" model
• Covalent Bonds: Sharing electrons between nonmetals

Molecular Geometry

• Lewis Dot Structures & Resonance
• VSEPR Theory: Predicts molecular shapes
• Hybridization: sp, sp2, sp3 depending on electron pairs

Unit 3: Intermolecular Forces and Properties

Intermolecular Forces (IMFs)

• Dipole-Dipole: Attractions between polar molecules
• Hydrogen Bonds: Strong dipole-dipole with H bonded to N, O, F
• London Dispersion Forces (LDFs): Weak attractions in all molecules
• IMF Strength: Influences boiling/melting points, vapor pressure

Unit 4: Chemical Reactions

Reaction Types

• Synthesis, Decomposition, Redox, Acid-Base
• Precipitation: Formation of a solid

Chemical Equations

• Stoichiometry: Based on mole ratios
• Oxidation States & Redox Reactions

Unit 5: Kinetics

Rate Laws

• Rate Law Expression: Based on reactant concentrations
• Reaction Order: Defines rate dependency
• Collision Theory: Reactions occur when molecules collide with sufficient energy

Unit 6: Thermodynamics

Enthalpy

• Endothermic vs. Exothermic: Energy absorption vs. release
• Hess’s Law: Total enthalpy change is sum of changes

Entropy & Gibbs Free Energy

• Entropy (S): Measure of disorder
• Gibbs Free Energy (G): Predicts reaction spontaneity

Unit 7: Equilibrium

Equilibrium Constant (K)

• Law of Mass Action: Relation of product/reactant concentrations
• Le Chatelier’s Principle: System response to stress

Unit 8: Acids and Bases

pH and pOH

• pH Scale: Measures acidity/basicity
• Acid/Base Strength: Dissociation in water
• Buffers: Resist pH changes

Unit 9: Applications of Thermodynamics

Electrochemistry

• Galvanic Cells: Convert chemical energy to electrical energy
• Electrolytic Cells: Use electricity to drive non-spontaneous reactions

Reduction Potentials

• Voltage & Favorability: Linked to Gibbs free energy

Note: These notes are a high-level overview; detailed study and understanding of each topic and subtopic are necessary for mastering AP Chemistry.