Bohr adapted Rutherford’s nuclear atom to the quantum theory of Max Planck.
Rutherford’s 1911 model placed nearly all an atom’s positive charge and mass in a tiny nucleus, with electrons outside it. The model explained scattering experiments but created a major problem: according to classical electrodynamics, orbiting electrons should radiate energy, spiral into the nucleus, and make atoms unstable.
Bohr addressed that problem by applying Planck’s idea that energy is exchanged in discrete amounts. In his 1913 atomic model, electrons could occupy only certain quantized “stationary states.” An electron emitted or absorbed radiation when it jumped between allowed energy levels, with the energy difference related to the radiation’s frequency.
This framework successfully explained the spectral lines of hydrogen, including the Balmer series, although the original Bohr model was later superseded by full quantum mechanics. Max Planck’s theory was therefore the key quantum ingredient; Einstein, Dirac, and de Broglie made other crucial contributions to quantum physics but were not the answer to this question.