Alpha, beta and gamma decay

Answer Key - Grade 10 Science Worksheet

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

1. 1.

   Iodine has atomic number 53. One of its isotopes gives off a beta particle. What is the new atomic number, Ari?

   54
2. 2.

   Carbon has atomic number 6. One of its isotopes gives off a beta particle. What is the new atomic number, Bo?

   7
3. 3.

   Cobalt has atomic number 27. One of its isotopes gives off a beta particle. What is the new atomic number, Esme?

   28
4. 4.

   Uranium-238 (92 protons) gives off an alpha particle. What forms, Jun?

   • Thorium-236, 90 protons
   • Thorium-234, 90 protons
   • Uranium-234, 92 protons
5. 5.

   Radium-226 (88 protons) becomes radon-222 (86 protons). What is given off, Luz?

   • A beta particle and a gamma ray
   • A gamma ray
   • An alpha particle
6. 6.

   A nucleus's mass number drops by 4 and its atomic number by 2. Which decay is it, Milo?

   • Beta
   • Gamma
   • Alpha
7. 7.

   A nucleus gives off energy but keeps its mass and atomic numbers. Which decay is it, Pia?

   • Gamma
   • Alpha
   • Beta
8. 8.

   What must add up to the same total on both sides of a nuclear equation, Ren?

   • The colors of the substances
   • The number of molecules
   • Mass numbers and atomic numbers
9. 9.

   Why is a beta particle written with atomic number −1, Tala?

   • It carries a −1 charge
   • It has a mass of 1
   • It has one proton
10. 10.

    In beta decay, what happens inside the nucleus, Zee?

    • Two protons leave the nucleus
    • A neutron becomes a proton
    • A proton becomes a neutron