Electron Movement and Wavelengths of Light

This simulation shows how electrons absorb energy, move to higher energy levels, and then release energy as light when they fall back to lower energy levels. Different electron drops release different amounts of energy, producing different wavelengths and colors of light.

Choose an atom: Hydrogen Sodium Neon Mercury

Choose an electron drop:

1. Absorb Energy 2. Emit Light

n = 1

n = 2

n = 3

n = 4

+

Energy absorbed

Choose an atom and an electron transition. Then click Absorb Energy followed by Emit Light.

Hydrogen Emission

Hydrogen produces specific lines of light because its electrons can only move between specific energy levels.

Light Produced

---

Wavelength: --- nm

Relative energy: ---

No light emitted yet

Visible Spectrum

400 nm 500 nm 600 nm 700 nm

Shorter wavelengths have higher energy. Longer wavelengths have lower energy.

Key Idea

When an electron falls from a higher energy level to a lower energy level, the atom releases a photon.

Larger energy drop → higher energy photon → shorter wavelength.

Smaller energy drop → lower energy photon → longer wavelength.

Why only certain colors?

Electrons cannot exist between energy levels. Because only certain electron transitions are allowed, atoms release only certain wavelengths of light. This creates a unique bright-line spectrum for each element.

Student Questions

1. What happens to the electron when energy is absorbed?
2. What happens when the electron falls back down?
3. Which transition produces the shortest wavelength?
4. Why do different elements produce different colors of light?