2: Atoms, Molecules, and Ions Last updated Jun 23, 2019 Save as PDF 1.12: Practice Questions 2.1: Chemistry and the Elements Page ID95109 ( \newcommand{\kernel}{\mathrm{null}\,}\) Topic hierarchy2.1: Chemistry and the Elements2.2: Elements and the Periodic Table2.3: Some Common Groups of Elements and Their Properties2.4: Observations Supporting Atomic Theory - The Conservation of Mass and the Law of Definite Proportions2.5: The Law of Multiple Proportions and Dalton's Atomic Theory2.6: Atomic Structure - Electrons2.7: Atomic Structure - Protons and Neutrons2.8: Atomic Numbers2.9: Atomic Weights and the Mole2.9.1: The Concept of Mole and the Avogadro Constant2.10: Mixtures and Chemical Compounds; Molecules and Covalent Bonds2.11: Ions and Ionic Bonds2.12: Naming Chemical Compounds