2.3.3 Half-life and Radioactive Decay

• Radioactivity is the spontaneous decay of unstable atomic nuclei to release radiation.
• Match the key terms with their definitions:

  Radioactive Decay ↔️ Spontaneous breakdown of unstable nuclei

  Half-life ↔️ Time taken for half the nuclei to decay
• Stable atomic nuclei do not emit radiation because they possess balanced forces.
• The half-life of a radioactive isotope indicates how quickly the material will decay over time.
• Radioactivity is the spontaneous decay of unstable atomic nuclei to release radiation.
• Stable nuclei undergo radioactive decay

  False
• Half-life is the time taken for half of the radioactive nuclei in a sample to decay.
• Radioactive decay involves the release of alpha, beta, or gamma particles.
• Half-life is a measure of the rate of radioactive decay.
• In the half-life formula, \( N_0 \) represents the initial amount of the substance.
• Stable atomic nuclei do not undergo radioactive decay because they possess balanced forces.
• What is radioactive decay?

  Emission of radiation by unstable nuclei
• What does half-life measure?

  Rate of radioactive decay
• Match the number of half-lives with the remaining amount of a radioactive sample:

  0 ↔️ 100%

  1 ↔️ 50%

  2 ↔️ 25%

  3 ↔️ 12.5%
• After three half-lives, 25% of the original sample remains

  False
• Radioactive decay is the spontaneous process where unstable atomic nuclei emit radiation to become more stable.
• Radioactivity is the spontaneous decay of unstable atomic nuclei to release radiation.
• Half-life is the time taken for half of the radioactive nuclei in a sample to decay.
• The formula for calculating half-life is \( N_t = N_0 \left( \frac{1}{2} \right)^{\frac{t}{T}} \).
• After one half-life, 50% of the original radioactive material remains.
• Radioactivity involves the spontaneous decay of unstable atomic nuclei
• An alpha particle is a helium-4 nucleus
• Half-life does not depend on the initial amount
• What is the formula for calculating half-life?

  N_t = N_0 \left( \frac{1}{2} \right)^{\frac{t}{T}}</latex>
• The half-life of carbon-14 is used in carbon dating
• Stable atomic nuclei do not undergo radioactive decay because they have balanced forces.
• The half-life of a radioactive isotope is constant and does not depend on the sample size.
• After radioactive decay, a nucleus becomes more stable than it was before.
• Half-life is the time it takes for half of the radioactive nuclei in a sample to decay.
• In the half-life formula, \( t \) represents the total time elapsed.
• What is radioactivity?

  Spontaneous decay of unstable nuclei
• Match the key terms with their definitions:

  Alpha Particle ↔️ Helium-4 nucleus

  Beta Particle ↔️ High-energy electron or positron

  Gamma Ray ↔️ High-energy photon
• Steps to explain how half-life works

  1️⃣ Define half-life

  2️⃣ Describe constant decay rate

  3️⃣ Provide an example
• Order the steps to calculate the remaining amount after a given number of half-lives

  1️⃣ Identify the initial amount

  2️⃣ Identify the half-life

  3️⃣ Calculate the number of half-lives

  4️⃣ Apply the half-life formula
• Half-life is the time taken for half of the radioactive nuclei in a sample to decay
• Half-life is a constant property for each radioactive isotope
• In the half-life formula, \( N_t \) represents the amount remaining after time t
• Understanding half-life is crucial for scientific dating techniques