"Version: 20180401"--Title page verso."A Morgan & Claypool publication as part of IOP Concise Physics"--Title page verso.Includes bibliographical references.1. The Bohr atom -- 1.1. Spectral lines -- 1.2. Center of mass -- 1.3. Atomic units -- 1.4. Isotopes and exotic atoms2. Quantum mechanics -- 2.1. Formalism -- 2.2. Spin -- 2.3. Wave mechanics3. One-electron atoms -- 3.1. Two-body systems --…