---
title: "Energy Level Diagram — AP Physics 2 Definition & Guide"
description: "An energy level diagram maps an atom's allowed electron energies as horizontal lines, letting you calculate photon energies for absorption and emission jumps."
canonical: "https://fiveable.me/ap-physics-2-revised/key-terms/energy-level-diagram"
type: "key-term"
subject: "AP Physics 2"
---

# Energy Level Diagram — AP Physics 2 Definition & Guide

## Definition

An energy level diagram is a visual representation that shows the different energy levels or orbitals of an atom or molecule. It illustrates how electrons are distributed in these energy levels.

## Related Study Guides

- [7.1 Systems and Fundamental Forces](/ap-physics-2-revised/unit-7/systems-fundamental-forces/study-guide/wMf1jbCx3U2CX46l9YcK)

## Review

### Related Terms

- [Ground-State Electron](/ap-physics-2-revised/key-terms/ground-state-electron): A ground-state electron refers to an electron that occupies the lowest available energy level in an atom or molecule.
- Excited State: An excited state occurs when an electron absorbs energy and moves to a higher energy level than its ground state.
- [Photon](/ap-physics-2-revised/key-terms/photon): A photon is a particle of light that carries a specific amount of energy. It can be emitted or absorbed by electrons during transitions between energy levels.