Nuclear Chemistry

• Study of nuclear reactions and their uses in chemistry.
• If the nucleus were the size of a ping pong ball, the electron in the 1s orbital would be 0.5 km away with a mass of 2.5 billion tons and energy millions of times larger than normal chemical reactions.

Uses of Radioactive Elements

• Medicine: diagnostic tools and treatments.
• Determine mechanisms of chemical reactions.
• Trace movement of atoms in biological systems.
• Date historical artifacts.
• Generate electricity and create weapons of mass destruction.

Section 1: Nuclear Stability and Radioactive Decay

• Nucleons: protons (p+) and neutrons (n0).
• Atomic Number: Number of protons.
• Mass Number: Number of protons and neutrons.
• Isotopes: Atoms with the same number of protons but different number of neutrons.
• Radionuclides: Unstable nuclei that spontaneously emit particles and radiation.
• Zone of Stability: Stability of nuclei based on proton to neutron ratio.
• Types of Radioactive Decay:
  • Alpha (α): Stream of helium-4 particles (e.g., 238U → 234Th + 42He).
  • Beta (β): High-speed electrons emitted by an unstable nucleus (e.g., 238U → 238Np + 0-1e).
  • Gamma (γ): High-energy photons released during nuclear reorganization.
  • Positron Emission: Converts a proton into a neutron (e.g., 116C → 115B + 01e).
  • Electron Capture: Nucleus captures an inner-shell electron (e.g., 8137Rb + 0-1e → 8136Kr).

Section 2: The Kinetics of Radioactive Decay

• Neutron-to-Proton Ratio: Determines stability; more neutrons needed as the number of protons increases.
• Radioactive Series: Series of nuclear reactions leading to a stable nucleus.
• Magic Numbers: More stable nuclei have 2,8,20,28,50,82 protons or neutrons.
• Half-life: Time required for half of a substance to decay.
  • Strontium-90 half-life example.
• Calculations:
  • ln(Nt/N0) = -kt
  • T1/2 = 0.693/k

Section 3: Nuclear Transformations

• Nuclear Reactions: Induced by neutron or nucleus collision.
• Charged Particles: Requires high speed to overcome repulsion.
• Neutron Use: Common in synthetic isotope production.
• Transmutation Elements: Elements with atomic numbers above 92.

Section 4: Detection and Uses of Radioactivity

• Detection Methods:
  • Photographic plates.
  • Geiger counters.
  • Scintillation counters.
  • Radiotracers.
• Uses in Dating:
  • C-14 for organic materials.
  • U-238 to Pb-206 for rocks.

Section 5: Thermodynamic Stability of the Nucleus

• E = mc^2: Energy-mass equivalence.
• Nuclear Binding Energies: Stability towards decomposition.
• Fission: Heavy nuclei stabilize by splitting.
• Fusion: Light nuclei combine to release energy (e.g., the Sun).

Section 6: Nuclear Fission and Nuclear Fusion

• Fission: Used in power plants and weapons.
• Chain Reaction: Critical mass needed to sustain reactions.
• Nuclear Reactors: Use fissionable material like U-235.
• Fusion: High energy requirements; not used for energy production.

Section 7: Effects of Radiation

• Radiation Damage:
  • Somatic: Affects the organism.
  • Genetic: Affects offspring.
• Factors:
  • Energy (rads).
  • Penetrating ability (gamma > beta > alpha).
  • Ionizing ability.
  • Chemical properties.
• Radiation Doses:
  • Becquerel (Bq), Curie (Ci), Gray (Gy), Rad.

Additional Topics

• Gryffinium Production: Example of synthetic element creation.
• Environmental Radiation: Includes various natural and artificial sources.
• Ionizing Radiation: Harms living tissues by creating highly reactive ions and radicals.