| 4.1 - Atomic Mass | .... page 80 |
| 4.3 - Subatomic Particles: Electrons, Protons, and Neutrons | .... page 82 |
| 4.4 - Electrons, Protons, and Neutrons. Atomic Number | .... page 83 |
| 4.5 - Isotopes | .... page 85 |
| 4.6 - Arrangement of Electrons in Principal Energy Levels | .... page 87 |
| 4.7 - Electron-Dot Formulas of Elements | .... page 89 |
| 4.8 - Arrangement of the Electrons in Sublevels | .... page 91 |
| 4.9 - Orbitals | .... page 97 |
