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.

   Uranium with mass number 238 decays through 8 alpha and 6 beta steps to a stable lead isotope. What is lead's mass number, Ari?

   206
2. 2.

   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
3. 3.

   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
4. 4.

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

   • 82, lead
   • 98, californium
   • 70, ytterbium
5. 5.

   Which decay changes the element but not the mass number, Kira?

   • Alpha
   • Beta
   • Gamma
6. 6.

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

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

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

   • Agree: carbon changes, as in decay
   • Agree: carbon turns into oxygen
   • Disagree: burning only rearranges atoms
8. 8.

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

   • Agree: gamma adds a proton
   • Agree: gamma takes away 4 nucleons
   • Disagree: it gives off energy only
9. 9.

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

   • Neutrons
   • Alpha particles
   • Beta particles
10. 10.

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

    • Helium gas
    • Gamma rays
    • Alpha particles