---
title: "Lattice Energy — AP Chem Definition & Exam Guide"
description: "Lattice energy is the energy needed to separate an ionic solid into gaseous ions. On the AP Chem exam, you predict it using Coulomb's law, ion charge, and ion size."
canonical: "https://fiveable.me/ap-chem/key-terms/lattice-energy"
type: "key-term"
subject: "AP Chemistry"
---

# Lattice Energy — AP Chem Definition & Exam Guide

## Definition

This is the energy required to break apart an ionic compound and convert its component atoms into gaseous ions.

## Related Study Guides

- [2.3 Structure of Ionic Solids](/ap-chem/unit-2/structure-ionic-solids/study-guide/3khaTI6A3tdnaMTMJy2u)

## Review

### Related Terms

- Ionic Compound: These are compounds composed of ions, charged particles that form when an atom gains or loses electrons. In our analogy, these are the individual lego blocks.
- [Ionization Energy](/ap-chem/key-terms/ionization-energy): This is the energy required to remove an electron from a neutral atom. It's like trying to take a tiny piece off one of your lego blocks.
- [Electron Affinity](/ap-chem/key-terms/electron-affinity): This is the amount of energy released when an electron is added to a neutral atom. It's like if adding another small piece onto your lego block made it suddenly become more stable and release energy.