AP Chemistry Complete Review and Exam Guide 2027
Prepare by representation, calculation, and evidence
AP Chemistry · Complete ReviewAP Chemistry Complete Review and Exam Guide 2027
- 58-page review
- 9 units
- 60 MCQs · 7 FRQs
AP Chemistry asks you to move among particle diagrams, equations, graphs, numerical data, and laboratory evidence. The exam lasts 3 hours and 15 minutes: 60 multiple-choice questions in 90 minutes and 7 free-response questions in 105 minutes, with each section worth 50% of the score.
- How AP Chemistry is assessed Both sections recommend a scientific or graphing calculator; the free-response section contains 3 long and 4 short questions.
- How to use the review Name the requested quantity or claim, choose evidence that answers it, show units and signs, and check the result against the chemical model.
- Reference-sheet readiness Practice choosing relationships from the provided equations and constants sheet while memorizing common ion formulas, solubility rules, and other facts that are not printed there.
- Independent practice Worked numbers, settings, and explanations are written for this guide rather than copied from official questions.
What AP Chemistry covers
The course has nine units in the order shown below. Each percentage is a published range for multiple-choice content, not a promised question count and not a free-response quota.
AP Chemistry timing, questions, and calculator use
The two sections have equal score weight. Calculator guidance is stated separately for each section so your practice setup matches the task you are doing.
| Total testing time | 3 hours and 15 minutes |
|---|---|
| Section I · Multiple Choice | 60 questions · 90 minutes · 50% of the exam score · scientific or graphing calculator recommended for this section |
| Section II · Free Response | 7 questions · 105 minutes · 50% of the exam score · scientific or graphing calculator recommended for this section |
| Free-response mix | 3 long questions (10 points each) and 4 short questions (4 points each) |
Check current exam details at College Board — AP Chemistry exam. Official information shown here is current as of 2026-08-29.
Read a spectrum and preserve the electron count
This independently written example keeps the problem, work, and answer separate, then checks four scoring decisions one by one.
- Step 1Work — Neutral Q has 24 electrons; Q³⁺ therefore has 24 e⁻ − 3 e⁻ = 21 e⁻. Starting from the neutral pattern [Ar] 3d⁵ 4s¹, remove the 4s electron before two 3d electrons: Q³⁺ = [Ar] 3d³. The tallest signal is 80.0%, so mass 52 is most abundant. The two isotopes have the same 24 protons; mass 53 has 53 − 24 = 29 neutrons, one more than mass 52.
- Step 2Keep the three targets independently readable: mark which signal supplies abundance, which count supplies elemental identity, and which charge operation supplies the electron total. A correct configuration cannot repair an unsupported isotope claim, so place the local evidence beside each conclusion and carry an earlier result forward only when the next task actually depends on it.
- Step 3Trace each conclusion back to one local observation: signal intensity supports abundance, atomic number preserves elemental identity, mass difference changes neutron count, and ionic charge determines the electron adjustment. If one part is uncertain, keep the other evidence chains explicit; a finished configuration does not supply missing support for an isotope comparison.
| Rubric point | Model element | Common error | Credit |
|---|---|---|---|
| Electron total | Shows 24 − 3 = 21 electrons. | Adds electrons for a positive ion. | Earned |
| Configuration | Removes 4s before 3d and writes [Ar] 3d3. | Deletes the last symbols as printed without considering energy. | Earned |
| Spectrum | Uses the 80.0% signal to identify mass 52. | Calls the rightmost peak the most abundant. | Earned |
| Isotope reason | Keeps proton count fixed and finds a one-neutron difference. | Changes proton count and therefore changes the element. | Earned |
Keep three counts separate. Atomic number counts protons; ionic charge changes electrons; isotope mass changes neutrons. One number cannot stand in for all three.
Fifteen AP Chemistry terms with definitions
These fifteen definitions are selected from the review appendix. Use each term as an instruction about what evidence to read or what feature to show, not as an isolated flash-card label.
- atomic number
- The proton count that fixes an element's identity.
- isotope
- An atom of the same element with a different neutron count.
- mass spectrum
- A display whose signal positions and relative intensities reveal mass-to-charge values and abundance.
- electron configuration
- A notation showing how an atom or ion's electrons occupy subshells.
- valence electron
- An electron in the outer occupied energy levels that commonly participates in bonding or ion formation.
- effective nuclear charge
- The net attractive influence an electron experiences after shielding is considered.
- shielding
- Reduction of nucleus–electron attraction caused by other electrons between them.
- ionization energy
- Energy required to remove an electron from a gaseous atom or ion under the stated step.
- atomic radius
- A measure of atomic size inferred from a defined internuclear distance or model.
- Lewis structure
- A bonding model that displays bonds and nonbonding valence electrons.
- formal charge
- An electron-bookkeeping value used to compare plausible bonding contributors.
- resonance
- Use of multiple electron placements with the same atom skeleton to describe delocalization.
- electron domain
- One bonding region or lone-pair region around a central atom.
- molecular geometry
- The arrangement of bonded atoms around a selected center, excluding lone pairs from the shape name.
- London dispersion
- Attraction arising from temporary, correlated fluctuations in electron clouds.
AP Chemistry FAQ
How is the AP Chemistry exam divided?
The exam lasts 3 hours and 15 minutes. The 60-question multiple-choice section lasts 90 minutes and counts for 50%; the 7-question free-response section lasts 105 minutes and counts for 50%.
What calculator should a student use?
A scientific or graphing calculator is recommended for both sections.
Are equations and constants provided?
Yes. The exam provides an equations and constants reference; students still need to choose the correct relationship and know chemical facts not listed there.
Are the practice numbers copied from published questions?
No. Practice settings and numerical values in this guide are independently written and labeled as illustrative.
What must I memorize if the exam provides equations and constants?
The exam provides an equations and constants sheet, but it does not list every fact you need. Memorize common ion formulas, solubility rules, and other required chemical facts that are not printed on the sheet.
Are the multiple-choice questions in this review official released questions?
No. The public materials available for this review do not include officially released multiple-choice questions. The multiple-choice format page explains the official framework with independently written examples; it is not a collection of official questions.
How to study for AP Chemistry
Read each worked page in three passes. First identify the requested particle, quantity, graph feature, or explanation. Next reproduce the calculation or reasoning with units and signs visible. Finally audit every row of the four-column scoring check.
Translate before calculating. Move deliberately among particulate, symbolic, graphical, and macroscopic evidence. Write what each axis, coefficient, concentration, charge, or temperature measures before selecting an equation.
Use weight ranges to schedule practice, not to predict the test. Give Properties of Substances and Mixtures and Acids and Bases longer review blocks, then keep all seven 7-9% units active in mixed sets. Published ranges never guarantee a fixed item count.
Practice with and without the reference sheet. With the sheet open, find the correct relationship quickly and state its assumptions. With it closed, recall common ions, solubility rules, particle conventions, and the chemical facts the sheet does not supply.
