AP Exam Prep · AP Chemistry

AP Chemistry Unit 2 Practice Test: Compound Structure and Properties

Unit 2 explains how atoms are held together and how that shapes a substance. Expect questions on bond type, lattice strength, alloys, Lewis structures, resonance and molecular shape.

Exam weighting:
7–9%
Questions:
12 multiple choice
Time:
about 16 minutes
Cost:
Free, no sign-up

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Question 1 of 12 · 0 answered

Question 1

Topic 2.1 · Apply it

A white solid doesn't conduct electricity, but it does when melted or dissolved in water. It has a very high melting point. What kind of bonding does it most likely have?

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What AP Chem Unit 2 covers

Unit 2, Compound Structure and Properties, makes up 7–9% of the multiple-choice section and usually takes ~12–13 class periods. These are the topics in the current course framework, and every question in the test above is tagged with one of them.

  1. 2.1Types of Chemical Bonds
  2. 2.2Intramolecular Force and Potential Energy
  3. 2.3Structure of Ionic Solids
  4. 2.4Structure of Metals and Alloys
  5. 2.5Lewis Diagrams
  6. 2.6Resonance and Formal Charge
  7. 2.7VSEPR and Hybridization

Unit 2 key ideas

Bond type follows electronegativity

Large electronegativity differences give ionic bonding, smaller ones give polar covalent bonds, and metals share a sea of delocalised electrons.

Potential energy sets bond length

On a potential energy curve, the minimum marks the bond length and its depth shows bond energy. Multiple bonds are shorter and stronger.

Ionic and metallic structures

Lattice strength rises with ion charge and falls with ion size. Substitutional alloys swap similar-sized atoms; interstitial alloys fit small atoms into gaps, making the metal harder.

Lewis structures predict shape

Count valence electrons, minimise formal charges and use resonance where needed. VSEPR then predicts geometry from electron domains, which links to hybridization.

Common Unit 2 mistakes

  • Counting electron domains but forgetting that lone pairs change the molecular shape.
  • Thinking resonance structures flip back and forth instead of describing one delocalised structure.
  • Predicting lattice energy from formula size rather than ion charge and radius.

How to study this unit

  • Practise drawing Lewis structures for the common ions and molecules until you can do them quickly.
  • For each shape, learn the electron-domain geometry, molecular geometry, bond angle and hybridization together.

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More AP Chemistry practice tests

← Unit 1: Atomic Structure and PropertiesUnit 3: Properties of Substances and Mixtures →

About these questions

StudyCoach wrote these questions for this test. Each one is mapped to a topic in the College Board's current AP Chemistry course framework. Every answer key was also checked by a separate AI review, and any disagreement was rechecked by hand. They have not yet been reviewed by an AP Chemistry teacher. If you think an answer is wrong, email support@studycoach.io.

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