Waves Progressive wave (animation) Electromagnetic waves Quanta The Bohr atom Detail of Bohr's theory Calculation of λ and ΔE with Bohr's theory Quantum mechanics Waves and matter (exercises) Waves and energy (exercises) Electron levels in atoms Fill order of the energy levels in an atom Atomic orbitals Atomic orbitals (animation et details) Electron structure of atoms (animation) Electron structure of atoms (exercises) The outer (valence) electrons The outer (valence) electrons and the coloration of flames Semi-conductors Diodes LEDs The Lewis structure of atoms The Lewis structure of ions Table of Lewis structures of atoms Table of Lewis structures of ions