Alpha, beta and gamma decay

Answer Key - Grade 10 Science Worksheet - Building Confidence

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

1. 1.

   Polonium with mass number 210 gives off an alpha particle. What is the new mass number, Ari?

   206
2. 2.

   Uranium with mass number 238 gives off an alpha particle. What is the new mass number, Bo?

   234

3. Read this first

   Nuclear notation

   Before and after (OpenStax §21.3). Columns: decay, before, given off, after. alpha, polonium-210 (84 protons), helium-4 nucleus (2 protons), lead-206 (82 protons); beta, iodine-131 (53 protons), electron (charge −1), xenon-131 (54 protons); gamma, excited cobalt-60 (27 protons), gamma ray (no mass, no charge), cobalt-60 (27 protons).

4. 3.

   Using the card, what does alpha decay give off, Jun?

   • A helium-4 nucleus
   • An electron from the shell
   • A gamma ray of light
5. 4.

   Using the card, what happens to the mass number in beta decay, Kira?

   • It rises by 1
   • It stays the same
   • It drops by 4 each time
6. 5.

   Using the card, what does gamma decay change, Luz?

   • The mass number
   • The number of protons inside
   • Only the nucleus's energy
7. 6.

   What is an alpha particle made of, Milo?

   • One electron and one proton
   • 2 protons and 2 neutrons
   • Pure light
8. 7.

   What is gamma radiation, Pia?

   • High-energy light
   • A heavy charged particle
   • A proton
9. 8.

   What changes in a nuclear change, Ren?

   • The color and the smell of the substance
   • The nucleus, so the element can change
   • The bonds that link separate atoms
10. 9.

    What changes in a chemical change, Tala?

    • The mass numbers
    • The number of protons
    • Bonds and electrons
11. 10.

    Which of these is a nuclear change, Zee?

    • Methane burning in a stove
    • Iron rusting in damp air
    • Carbon-14 becoming nitrogen-14