Nuclear Radiation Types and Properties

Key Concepts

• Elements have different forms called isotopes (same protons, different neutrons).
• Only one or two isotopes of an element are stable; others are unstable and can undergo radioactive decay to become stable.
• Radioactive materials contain unstable isotopes that decay.

Types of Nuclear Radiation

• Alpha Particles

  • Composed of 2 protons and 2 neutrons (similar to helium nucleus).
  • Represented by helium's nuclear symbol (He).
  • Overall charge: +2 (due to lack of electrons).
  • Properties:
    • Large in size, easily stopped by collisions.
    • Penetration: Can travel only a few centimeters in air, absorbed by paper.
    • Ionizing ability: Very strong, easily knocks off electrons from atoms.

• Beta Particles

  • Essentially electrons with a charge of -1 and negligible mass.
  • Origin: Not from electron shells but from neutron decay (neutron becomes a proton and an electron; electron is emitted).
  • Properties:
    • Moderately ionizing.
    • Penetration: Travels several meters in air, stopped by 5 mm of aluminum.

• Gamma Rays

  • Not particles, but waves of electromagnetic radiation.
  • Often emitted to release extra energy, following alpha or beta decay.
  • Properties:
    • Massless and charge-less, weakly ionizing.
    • Penetration: Passes through materials easily; requires thick lead or concrete to stop.

• Neutrons

  • Emission occurs if a nucleus has excess neutrons.
  • Purpose: Increases stability by releasing a neutron.

Recap

• Alpha Particles: Stopped by paper.
• Beta Particles: Stopped by thin aluminum.
• Gamma Rays: Require thick lead to be stopped.

Conclusion

• Understanding the different types of radiation is crucial for knowing their penetration and ionization capabilities.