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Hydrogen-like species: wavelength ratio, atomic number and ionic charge
JEE Advanced 2026
Paper 2 · Question 10
Chemistry
Bohr model of hydrogen-like species and the Rydberg equation
Moderate
Build a hydrogen-like ion proton by proton, fire tuned photons at it and watch the electron jump, hunt the pair of atomic numbers that makes one wavelength exactly nine times the other, then count the particles to turn Z into the ionic charge.
Open the interactive simulationSub-topics covered
- Hydrogen-like species and the one-electron condition
- Energy levels and the Z-squared scaling
- Absorption and emission transitions
- Rydberg equation and the ratio of two wavelengths
- Wavelength versus photon energy
- Atomic number versus ionic charge
What it teaches
- Hydrogen-like means exactly one electron, not one proton
- The Bohr result E = -13.6 Z^2 / n^2 holds only for a one-electron species
- Dividing two Rydberg equations cancels the constant and the wavelength alike
- Longer wavelength means lower photon energy, never higher
- The charge on a hydrogen-like ion is Z - 1, so the question is one subtraction longer than it looks
Simulation ID
- ADV-2026-P2-CHE-Q10 · revision 1
See this simulation in the library → · open the simulation file on its own