High school · Aligned to AP Chemistry
Chemistry: Atoms to AP Chemistry — study guide & practice questions
Atoms, bonds and reactions through AP Chemistry: IMFs, kinetics, equilibrium, acids and bases, thermodynamics, electrochemistry.
Study guide
Atomic Structure & Periodic Trends
- Protons and neutrons sit in the nucleus; electrons orbit in shells. Atomic number = protons; mass number = protons + neutrons.
- Atomic radius shrinks across a period and grows down a group; ionization energy and electronegativity trend the opposite way.
Chemical Bonding
- Ionic bonds transfer electrons (metal + nonmetal); covalent bonds share electrons (nonmetal + nonmetal).
- VSEPR theory predicts molecular shape from electron pair repulsion, which determines whether a molecule is polar.
Chemical Reactions & Equations
- A balanced equation has equal atoms of each element on both sides — adjust coefficients, never subscripts.
- Reactions classify as synthesis, decomposition, single/double replacement, or combustion; net ionic equations drop spectator ions.
The Mole & Stoichiometry
- A mole = 6.022 × 10²³ particles; molar mass bridges atomic-scale counts and measurable grams.
- Balanced-equation coefficients give mole ratios; the limiting reactant caps the theoretical yield.
States of Matter & Gas Laws
- Boyle's Law (P₁V₁ = P₂V₂) and Charles's Law (V₁/T₁ = V₂/T₂) describe gas behavior; PV = nRT ties pressure, volume, moles and temperature together.
- Temperature holds steady during a phase change while energy breaks or forms intermolecular forces instead.
Solutions
- Molarity = moles of solute ÷ liters of solution; dilution follows M₁V₁ = M₂V₂.
- Colligative properties (freezing point depression, boiling point elevation) depend on particle count, not identity.
Acids, Bases & pH
- Acids release H⁺, bases release OH⁻; pH below 7 is acidic, above 7 is basic, and each unit is a 10-fold change in H⁺.
- Acid + base → salt + water; titration uses M(acid)V(acid) = M(base)V(base) at the equivalence point.
Thermochemistry & Reaction Rates
- Exothermic reactions release energy, endothermic reactions absorb it; q = mcΔT calculates heat energy.
- Higher temperature, concentration, surface area, or a catalyst all speed up a reaction by affecting collisions or activation energy.
Nuclear Chemistry & Electrochemistry
- Alpha decay drops mass number by 4 and atomic number by 2; half-life is the constant time for half a sample to decay, so the amount remaining is (1/2)ⁿ after n half-lives.
- Oxidation is losing electrons, reduction is gaining them ("OIL RIG"); a galvanic cell uses a spontaneous redox reaction to generate electricity.
Course modules
9 foundation modules free to read here; 6 AP-level and advanced modules with Pro. Every module ends with a quiz in the app.
1. Atomic Structure & Periodic Trends Free
What atoms are made of, why isotopes exist, and the patterns the periodic table is built around.
Read the 4 lessons →2. Chemical Bonding Free
How and why atoms bond, how to name and write formulas for the results, and what shape they take.
Read the 4 lessons →3. Chemical Reactions & Equations Free
Writing, balancing, classifying, and predicting the products of chemical reactions.
Read the 4 lessons →4. The Mole & Stoichiometry Free
Counting atoms and molecules by the mole, and using balanced equations to relate amounts of reactants and products.
Read the 4 lessons →5. States of Matter & Gas Laws Free
How particle behavior explains the states of matter, and the laws that describe how gases respond to pressure and temperature.
Read the 4 lessons →6. Solutions Free
Concentration, solubility, dilution, and what happens to a solvent when something is dissolved in it.
Read the 4 lessons →7. Acids, Bases & pH Free
What makes something an acid or a base, how pH measures it, and what happens when they react.
Read the 4 lessons →8. Thermochemistry & Reaction Rates Free
How energy moves during reactions, and what speeds a reaction up or slows it down.
Read the 4 lessons →9. Nuclear Chemistry & Electrochemistry Free
How unstable nuclei decay, how to predict what's left over time, and how redox reactions generate electricity.
Read the 4 lessons →10. AP: Atomic Structure, PES & Coulomb's Law Pro · AP Chem · Unit 1
Explain periodic trends the way the AP exam demands — with Coulomb's law — and read photoelectron and mass spectra.
11. AP: Molecular Structure & Intermolecular Forces Pro · AP Chem · Units 2–3
Formal charge, resonance, hybridization, and how intermolecular forces decide boiling points, solubility, and the properties of solids.
12. AP: Chemical Kinetics Pro · AP Chem · Unit 5
Rate laws from data, integrated rate laws and half-life, and how reaction mechanisms connect to the observed rate law.
13. AP: Chemical Equilibrium Pro · AP Chem · Unit 7
Equilibrium expressions, Q vs K, ICE tables, Le Châtelier's principle, and solubility equilibria (Ksp).
14. AP: Acid–Base Equilibria & Buffers Pro · AP Chem · Unit 8
Ka/Kb calculations, weak-acid pH, buffers and the Henderson–Hasselbalch equation, and how to read titration curves.
15. AP: Thermodynamics & Electrochemistry Pro · AP Chem · Units 6 & 9
Hess's law, entropy, Gibbs free energy and its link to K and cell potential, and galvanic/electrolytic cells.
Sample practice questions
From module 1, Atomic Structure & Periodic Trends. Pick your answers, then check them in the app, with an explanation for every question.
1. Which group of elements has 1 valence electron and is highly reactive?
2. How does atomic radius change moving down a group?
Sample flashcards
4 of the cards in this course's deck. Tap a card to flip it.
Atomic StructureWhat are the three main subatomic particles, their charges, and where each is located?
Protons (positive, in the nucleus), neutrons (neutral, in the nucleus), and electrons (negative, orbiting in electron shells/clouds).
Atomic StructureHow does atomic number differ from mass number?
Atomic number = number of protons (defines the element); mass number = number of protons + neutrons (defines the isotope).
Periodic TrendsHow does atomic radius trend across a period (left to right) and down a group on the periodic table?
It decreases across a period (more protons pull electrons in tighter) and increases down a group (more electron shells are added).
Chemical BondingWhat is the difference between an ionic bond and a covalent bond?
Ionic bonds form when electrons are transferred between atoms (usually metal + nonmetal), creating oppositely charged ions that attract; covalent bonds form when atoms share electrons (usually nonmetal + nonmetal).
The full course is in LectureMate's Course Library: every module quiz with explanations, the complete flashcard deck with spaced repetition, and a 6-step strategy for AP Chemistry questions. Foundation modules are free; AP-level and advanced modules need Pro.