8.1 Radioactivity

• Match the source of radioactivity with its definition:

  Natural Radioactivity ↔️ Radioactive elements occurring naturally

  Artificial Radioactivity ↔️ Radioactive materials produced by humans
• Order the following types of radioactive decay by the particle emitted:

  1️⃣ Alpha Decay

  2️⃣ Beta Decay

  3️⃣ Gamma Decay
• Alpha decay reduces the atomic number by 2
• Beta decay can increase or decrease the atomic number by 1
• Match the decay type with its nuclear equation:

  Alpha Decay ↔️ ⁴²²²Ra → ⁴²¹⁸Rn + ⁴₂He

  Beta Decay ↔️ ¹⁴₆C → ¹⁴₇N + ⁰₋₁e

  Gamma Decay ↔️ ⁶⁰₂₇Co* → ⁶⁰₂₇Co + γ
• Order the protective measures against radioactive exposure from most effective to least effective:

  1️⃣ Shielding

  2️⃣ Distance

  3️⃣ Time
• What type of radiation is moderately ionizing and can penetrate the skin?

  Beta
• Match the protective measure with its effect:

  Shielding ↔️ Blocks radiation

  Distance ↔️ Reduces radiation intensity

  Time ↔️ Limits exposure duration
• The severity of radiation exposure depends on the type, dose, and duration of radiation.

  True
• Radioactivity is the spontaneous emission of radiation from unstable atomic nuclei
• What are examples of natural radioactive elements?

  Uranium, Thorium, Radon
• Order the types of radioactive decay from highest to lowest energy level:

  1️⃣ Alpha

  2️⃣ Beta

  3️⃣ Gamma
• In beta decay, an electron or positron is emitted, changing a neutron to a proton
• In alpha decay, the atomic number decreases by 2, and the mass number decreases by 4.

  True
• What is the composition of alpha particles?

  Helium nucleus
• Alpha particles are highly ionizing and dangerous if inhaled or ingested.


  True
• Half-life is the time it takes for half of the radioactive atoms in a sample to decay
• The radioactivity of a sample decreases by half with each passing half-life


  True
• By knowing the half-life of a radioactive material, we can calculate how much radioactivity will remain at any given time
• When an organism dies, the carbon-14 in its tissues continues to decay while the carbon-12 remains stable


  True
• Match the source of radioactivity with its description:

  Natural Radioactivity ↔️ Radioactive elements occurring naturally

  Artificial Radioactivity ↔️ Radioactive materials produced by humans
• In alpha decay, the nucleus emits an alpha particle
• Arrange the three types of radioactive decay in order of increasing penetrating power

  1️⃣ Alpha decay

  2️⃣ Beta decay

  3️⃣ Gamma decay
• In gamma decay, a gamma photon is emitted with no change in atomic number or mass number.
• Match the type of decay with the change in the nucleus:

  Alpha Decay ↔️ Atomic number -2, mass number -4

  Beta Decay ↔️ Atomic number +/- 1, mass number unchanged

  Gamma Decay ↔️ No change in atomic or mass number
• In beta decay, the atomic number changes by one while the mass number remains unchanged.
• Gamma decay reduces the energy state of the nucleus without changing its composition.


  True
• Arrange the types of radioactive decay in order of decreasing atomic number changes:

  1️⃣ Alpha Decay

  2️⃣ Beta Decay

  3️⃣ Gamma Decay
• Write the nuclear equation for alpha decay of ²²⁶₈₈Ra.

  ²²⁶₈₈Ra → ²²²₈₆Rn + ⁴₂He
• What is the composition of alpha particles?

  Helium nucleus
• Radioactivity is the spontaneous emission of radiation from unstable atomic nuclei
• Natural radioactivity is a fundamental property of certain elements.

  True
• Match the decay type with its description:

  Alpha Decay ↔️ Emission of a helium nucleus

  Beta Decay ↔️ Emission of an electron or positron

  Gamma Decay ↔️ Emission of a high-energy photon
• Alpha decay has the highest energy among the three types of radioactive decay.

  True
• Gamma decay emits a particle with a charge of +2.

  False
• Alpha particles are composed of two protons and two neutrons
• Alpha particles are highly ionizing but cannot penetrate the skin
• Gamma radiation is weakly ionizing but can penetrate deeply into the body.


  True
• What type of radiation is highly ionizing but cannot penetrate the skin?

  Alpha
• Match the source of radioactivity with its definition:

  Natural Radioactivity ↔️ Occurs naturally in the environment

  Artificial Radioactivity ↔️ Produced through human activities