Alpha, beta and gamma decay

Answer Key - Grade 10 Science Worksheet - Challenge Me

Circle the best answer, or write your answer on the line.

1. 1.

   Thorium with mass number 232 decays through 6 alpha and 4 beta steps to a stable lead isotope. What is lead's mass number, Bo?

   208
2. 2.

   Uranium with mass number 235 decays through 7 alpha and 4 beta steps to a stable lead isotope. What is lead's mass number, Esme?

   207
3. 3.

   Uranium-238 (92 protons) passes through 8 alpha and 6 beta decays. What is the final atomic number, Jun?

   • 70, ytterbium
   • 82, lead
   • 98, californium
4. 4.

   Oxygen-15 (8 protons) gives off a positron, charge +1. What forms, Luz?

   • Fluorine-15, 9 protons
   • Oxygen-14, 8 protons
   • Nitrogen-15, 7 protons
5. 5.

   Milo says carbon-14 becoming nitrogen-14 is a chemical change. Agree or disagree?

   • Disagree: the nucleus itself changes
   • Agree: a new substance forms, as in burning
   • Agree: carbon and nitrogen bond together
6. 6.

   Noah says burning wood turns its carbon atoms into a different element. Agree or disagree?

   • Agree: carbon turns into oxygen
   • Agree: carbon changes, as in decay
   • Disagree: burning only rearranges atoms
7. 7.

   Pia says gamma decay turns one element into another. Agree or disagree?

   • Agree: gamma adds a proton
   • Disagree: it gives off energy only
   • Agree: gamma takes away 4 nucleons
8. 8.

   Ionization smoke detectors use americium-241. What does it give off, Ren?

   • Neutrons
   • Alpha particles
   • Beta particles
9. 9.

   Technetium-99m is a medical tracer for scans. What does it give off that a camera detects, Tala?

   • Helium gas
   • Gamma rays
   • Alpha particles
10. 10.

    Carbon-14, used for dating, decays by which type of emission, Zee?

    • Alpha
    • Beta
    • Gamma alone