Answer:
(i) Bohr; (ii) de Broglie; (iii) Heisenberg (v) Schrödinger
Explanation:
(i) Niels Bohr — 1913 — proposed that electrons travel in fixed orbits with quantized energy levels and that they jump from one energy level to another by absorbing or emitting quanta of light.
(ii) Louis de Broglie — 1924 — proposed the wave nature of electrons and suggested that all matter behaves as both waves and particles (wave-particle duality).
(iii) Werner Heisenberg — 1927 — formulated quantum mechanics in terms of matrices and proposed his famous uncertainty principle.
(v) Erwin Schrödinger — 1926 — applied wave mechanics to the electron in a hydrogen atom, showing that electrons exist in orbitals rather that orbits.
(iv) Ernest Rutherford — 1911 — proposed that atoms have most of their mass in a central nucleus (nuclear atom). Quantum mechanics had not yet been invented.
