Lesson Plan

Describe Rutherford's gold foil experiment and the planetary model of the atom it produced

Describe the emission and absorption spectra of atoms and explain why they are discrete

Describe the Bohr model of the atom and how it explains the hydrogen spectrum

Calculate the energy absorbed or emitted when an electron changes energy levels

Calculate the frequency and wavelength of photons emitted when electrons change energy levels

Describe the quantum model of the atom and how de Broglie waves and the uncertainty principle motivate it

22.1

"Based on the size and mass of the nucleus revealed by his experiment, as well as the mass of electrons, Rutherford proposed the planetary model of the atom. The planetary model of the atom pictures low-mass electrons orbiting a large-mass nucleus." "His first conjecture was that only certain orbits are allowed: In other words, in an atom, the orbits of electrons are quantized. Each quantized orbit has a different distinct energy, and electrons can move to a higher orbit by absorbing energy or drop to a lower orbit by emitting energy." "Because of the wave characteristic of matter, the idea of well-defined orbits gives way to a model in which there is a cloud of probability, consistent with Heisenberg's uncertainty principle."