SECTION 19 - THE NUCLEUS AND NUCLEAR CHEMISTRY 19-1 -- The Nucleus • Protons and Neutrons • The Relative Size and Density of the Nucleus • The Energies Associated with Nuclear Reactions 19-2 -- Some Nuclear Definitions • Nucleons • Atomic Number (Z) and Mass Number (A) • Isotopes and Nuclides 19-2 -- Nuclear Stability and Radioactive Decay • A Typical Radioactive Decay Process 19-3 -- Types of Radioactive Decay Reactions • Alpha-Particle Production (α-particles) • Spontaneous Fission • Beta-Particle Production (β-particles) • Gamma Ray Production (γ-rays: photons) • Electron Capture • Positron Production (β + -particles) 19-5 -- Writing and Balancing Nuclear Reactions 19-5 -- Radioactive Decay Series 19-6 -- Half-Life (t ½ ) • Half-lives of Radioactive Nuclides • First-Order Decay Processes 19-6 -- Detection of Radioactivity • The Geiger Counter and Ar + (g) Detection 19-7 -- Carbon-14 Dating • Radioactive Decay and First-Order Kinetics 19-10 -- Nuclear Fission • Uranium-235 • Self-Sustaining Chain Reactions (subcritical, supercritical, and critical reactions) • Critical State and “Critical Mass” 19-12 -- Nuclear Fusion • Fusion Reactions in the Sun and in Stars • Fusion of Protons (H + ) to Form Helium (He) 19-13 -- Stability of the Nucleus 19-13 -- Mass Defect (Δm) • Calculating Nuclear Binding Energy from Mass Defect