Chapter 21: Nuclear Chemistry

21.1 Radioactivity and Nuclear Equations

• Isotopes: Same element, different mass due to varying neutrons.
• Radioactive nuclei emit radiation, termed radionuclides.
• Nuclear reactions involve nucleus changes, balancing atomic and mass numbers.

Types of Radioactive Decay

• Alpha decay: Loss of Helium nucleus (2 protons, 2 neutrons).
• Beta decay: Emission of high-speed electron from nucleus.
• Gamma decay: Emission of high-energy photon, often accompanying other decays.
• Positron emission: Proton converts to neutron, emits positron.
• Electron capture: Absorption of an electron into the nucleus.

21.2 Patterns of Nuclear Stability

• Stability from strong nuclear force.
• Proton/neutron ratios impact stability; 1:1 for small, more neutrons for large nuclei.
• Zone of Stability: Nuclei with balanced forces are stable.
• Unstable Nuclei: Beta decay above belt (too many neutrons), positron/electron capture below belt (too many protons).
• Magic numbers: Specific proton/neutron counts yield more stability.

21.3 Nuclear Transmutations

• Occur from nuclear collisions, use of particle accelerators.
• Particle Accelerators: Devices like linear accelerators, cyclotrons, synchrotrons used to induce transmutations.

21.4 Kinetics of Radioactive Decay

• First-order decay process, follows half-life equations.
• Radiometric Dating: Uses known decay rates for age estimation, e.g., Carbon-14.
• Table 21.5: Lists half-lives and decay types for radioisotopes.

21.5 Detection of Radioactivity

• Methods: Film badges, Geiger counters, scintillation counters.

21.6 Energy Changes in Nuclear Reactions

• E=mc²: Mass-to-energy conversion in nuclear reactions.
• Mass Defect: Missing mass translates to nuclear binding energy.

21.7 Nuclear Power

Fission

• Splitting heavy nuclei releases energy; chain reactions possible.
• Reactors use Uranium; control rods manage reactions.

Fusion

• Small nuclei combine; massive energy potential but requires extreme conditions.

Radiation in the Environment

• Ionizing radiation causes cellular ionization, potential damage.
• Radiation Dose: Measured in Grays and Rads; biological effect varies with type.

Effects of Exposure

• Acute exposure effects range from negligible to fatal based on dose.