Rutherford model

An atomic model in which a small, positively charged nucleus contains most of the atom’s mass, with electrons surrounding it. It emerged from evidence that atoms are mostly empty space.

Geiger–Marsden experiment: A 1909 scattering experiment in which alpha particles were directed at thin metal foil. Its rare large-angle deflections provided the evidence Rutherford used to infer a compact nucleus.
Atomic nucleus: The dense central region of an atom, containing protons and, except in ordinary hydrogen, neutrons. It is the compact, positively charged center at the heart of the model.
Electron: A stable elementary particle with negative electric charge, found in atoms and involved in chemical bonding. Electrons surround the nucleus in Rutherford’s picture, though the model did not explain their arrangement.
Bohr model: An atomic model in which electrons occupy quantized orbits around a central nucleus. Bohr kept Rutherford’s nucleus while adding stable electron orbits to explain hydrogen’s spectrum.
Ernest Rutherford: A physicist who established the nuclear theory of the atom and made major contributions to radioactivity. He interpreted the foil-scattering results as evidence for a concentrated positive nucleus.
Coulomb scattering: The deflection of charged particles by the electrostatic force between them. It describes how alpha particles are repelled by the model’s concentrated positive nucleus.
Proton: A positively charged subatomic particle found in atomic nuclei. Protons account for the positive charge concentrated in the model’s nucleus.
Quantum mechanical model: The modern description of atoms using quantum states and probability distributions rather than definite electron paths. It replaces the model’s classical surrounding electrons with quantum orbitals.
J. J. Thomson: A physicist who discovered the electron and proposed the plum pudding model of the atom. His diffuse-positive-charge model was displaced by Rutherford’s compact nucleus.
Rutherford scattering formula: A formula predicting the angular distribution of charged particles scattered by a point-like Coulomb center. Its predictions connect nuclear charge and geometry to the observed deflection pattern.

Linked from 12 pages