Question

How does the Bohr model of the atom explain the fixed colour lines seen in atomic spectra?

Answer 1

Bohr model:

• According to the Bohr model, the atom is composed of a small positive nucleus with electrons revolving in defined circular orbits around the nucleus.
• The energy levels of these circular orbitals are fixed.
• When an electron jumps from a lower energy level to a higher one, some energy is absorbed while some energy is emitted.
• The energy change is given by $∆\mathrm{E}=\frac{\mathrm{hc}}{\mathrm{\lambda }}$
• Since the energy levels of the orbitals are fixed, $∆\mathrm{E}$ are also constant for specific jumps.
• Hence, the wavelength is also the same for the same $∆\mathrm{E}$, thereby fixing the number of colour lines seen.

Therefore, the Bohr model of the atom explains the fixed colour lines seen in atomic spectra.