Radioactive Decay: Alpha, Beta and Gamma · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

Three kinds of nuclear radiation

Science · Matter & Materials · ages 15-16
Name ______________________   Date ____________

  1. What stops beta particles?

    • Paper or skin
    • A sheet of aluminium
    • Thin air alone

  2. What is an alpha particle?

    • A fast electron
    • A helium nucleus
    • A pure energy wave

  3. What changes in gamma decay?

    • Mass number drops by 4
    • Atomic number rises by 1
    • Both numbers stay the same, only energy leaves

  4. In a beta decay the parent has mass 14 and atomic number 6. What are the daughter numbers?

    • Mass 14, atomic 7
    • Mass 10, atomic 4
    • Mass 14, atomic 6

  5. In an alpha decay the parent has mass 238 and atomic number 92. What are the daughter numbers?

    • Mass 234, atomic 90
    • Mass 238, atomic 93
    • Mass 236, atomic 92

  6. A student writes a decay equation where the mass numbers do not balance. The equation can still be right.

    Circle one:   True   False

  7. Two sources sit one metre away, one alpha and one gamma. Which needs the heavier shielding?

    • The alpha source, with thick lead
    • Neither needs any shielding
    • The gamma source, with thick lead or concrete

  8. Why is an alpha emitter the worst kind to swallow but safe at arm's length?

    • Alpha stops in skin from outside but hammers tissue from inside
    • Alpha turns into gamma outside
    • Alpha cannot ionise at all
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Answer key

For grown-ups. Fold this page away before handing over the rest.

Three kinds of nuclear radiation W1-mt_-AmjVwkR9t-s1

  1. A sheet of aluminium · Beta crosses metres of air, so paper is not enough.
  2. A helium nucleus · Alpha is the chunky one, two protons plus two neutrons.
  3. Both numbers stay the same, only energy leaves · Gamma is an energy wave, not a particle loss.
  4. Mass 14, atomic 7 · Beta keeps the mass and raises the charge by one.
  5. Mass 234, atomic 90 · Subtract 4 on top and 2 below.
  6. False · Both columns must balance across every nuclear arrow.
  7. The gamma source, with thick lead or concrete · Gamma reaches far and needs dense shielding.
  8. Alpha stops in skin from outside but hammers tissue from inside · Range decides the danger, and alpha range is tiny.
Worksheet · LightMySky