Bohr Model (Hydrogen-like Atom)
Watch an electron drop between energy levels of a hydrogen-like atom and see the photon it gives off — pick the levels and the nuclear charge, and read the wavelength, energy and which series the line belongs to.
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What you can adjust
- Nuclear charge (Z)
- 1 – 3
- Initial level (n_i)
- 2 – 6
- Final level (n_f)
- 1 – 5
- Animation duration
- 1 – 4 s
How many protons the nucleus carries. Z=1 is hydrogen; Z=2 is singly-ionized helium (He+); Z=3 is doubly-ionized lithium (Li2+). A higher Z pulls the electron in tighter, so every transition emits a more energetic (shorter-wavelength) photon.
The energy level the electron starts on before it drops. Must be higher than the final level.
The energy level the electron drops to, emitting a photon. n_f=1 is the Lyman series, n_f=2 is Balmer (the only series with lines in visible light), n_f=3 is Paschen, and so on.
How long the clip runs — the electron orbits on the initial level, drops, then orbits on the final level.
About this simulation
What it shows
An electron in a hydrogen-like atom drops between energy levels and gives off a photon. The photon's wavelength, energy and spectral series are read out.
The key idea
Electrons can only sit at certain energy levels. Dropping from level n_i to n_f releases a photon with exactly the energy difference, and 1/λ = R Z² (1/n_f² − 1/n_i²). Drops to level 2 give the visible Balmer lines of hydrogen.
Try this
With Final level (n_f) at 2, raise Initial level (n_i) from 3 to 4: the photon changes from red (about 656 nm) to blue-green (about 486 nm).
This is the simple Bohr picture of an atom with one electron, which predicts the line wavelengths well. It does not show the electron cloud of a full quantum description.