Bohr Model of Hydrogen
Classroom worksheet · Interactive simulation: https://lkforge.com/tools/physics/bohr-model/
Name: Date:
Learning objectives
- Explain quantized energy levels in the hydrogen atom.
- Relate electron transitions to emitted or absorbed photons.
- Connect transitions to spectral lines.
Variables to change
- Initial energy level
- Final energy level
Procedure
- Excite the electron to a higher level and watch it drop back.
- Record the photon (color/wavelength) emitted for different transitions.
- Compare transitions ending on n=2 (visible series) with others.
Observations
Record which transitions emit visible light and how photon energy relates to the size of the energy jump.
Questions
- Why are only certain energies allowed?
- What determines the energy of an emitted photon?
- Which transitions produce visible light in hydrogen?
- What happens when the electron absorbs a photon?
- Why is the ground state (n=1) the most stable?
Answer key (instructors)
- 1. The Bohr model quantizes the electron’s orbits, so only discrete energy levels E_n = −13.6/n² eV exist.
- 2. The difference between the two levels: E_photon = E_high − E_low = hf.
- 3. The Balmer series — transitions ending at n = 2.
- 4. It jumps to a higher level, but only if the photon’s energy matches a level difference.
- 5. It is the lowest energy level; the electron cannot drop any lower, so it stays there unless excited.
In the Bohr model the hydrogen electron occupies quantized levels E_n = −13.6/n² eV. Dropping between levels emits a photon of energy equal to the gap (E = hf); the specific gaps produce the discrete spectral lines, with n→2 transitions giving hydrogen’s visible Balmer series.