8.2 Nuclear instability

• Nuclear instability occurs when a nucleus is prone to radioactive decay because of an imbalance in the proton-to-neutron ratio
• Too many neutrons in a nucleus may lead to beta-minus decay.
• Nuclei with lower binding energy per nucleon are more likely to be unstable


  True
• The weak nuclear force is responsible for beta decay.
• The line of stability plots stable nuclei based on their number of protons and neutrons


  True
• The line of stability is a graphical representation of stable nuclei based on their number of protons and neutrons
• In alpha decay, the nucleus emits an alpha particle, which consists of 2 protons and 2 neutrons
• What are two reasons for nuclear instability?

  Imbalanced nucleon ratio and excessive nuclear energy
• The weak nuclear force is responsible for beta decay and has a relative strength of 10⁻⁶ compared to the strong nuclear force.strength
• Radioactive decay is a nuclear reaction where unstable nuclei emit particles or energy
• What is the process called when a heavy nucleus splits into smaller nuclei?

  Fission
• The energy released during fusion is an example of a large energy release
• The half-life of a radioactive material is the time it takes for half of its nuclei to decay.
• What is the half-life of cobalt-60?

  5.27 years
• What formula is used to calculate the age of a sample using radioactive dating?

  N(t) = N_{0} \cdot e^{ - \lambda t}</latex>
• Nuclear instability always results in the emission of particles or energy to achieve a more stable configuration.


  True
• The strong nuclear force has a range of approximately 1 fm
• Match the nucleon ratio type with its corresponding decay mode:

  High Neutron ↔️ Beta-minus decay

  Low Neutron ↔️ Beta-plus decay

  Stable ↔️ None
• During beta-minus decay, a neutron converts into a proton, an electron, and an antineutrino
• Match the decay process with its required shielding:

  Alpha Decay ↔️ Paper or thin metal

  Beta-Minus Decay ↔️ Few millimeters of aluminum

  Gamma Decay ↔️ Thick lead or concrete
• Nuclear transmutation involves changing the number of protons in the nucleus.


  True
• What is the definition of half-life?

  Time for half decay
• What is the formula relating the decay constant (λ) to the half-life (T½)?

  $\lambda =$$\frac{\ln(2)}{T_{1 / 2}}$
• Match the radioactive dating technique with its corresponding isotope and half-life:

  Carbon-14 ↔️ ¹⁴C (5,730 years)

  Uranium-Lead ↔️ ²³⁸U (4.5 billion years)

  Potassium-Argon ↔️ ⁴⁰K (1.3 billion years)
• What type of shielding is required for gamma decay?

  Thick lead or concrete
• Which radioactive isotope is used in medical imaging to create images of the body?

  Technetium-99m
• Excessive nuclear energy in a nucleus often results in the emission of gamma rays to achieve stability.
• The strong nuclear force is the strongest of the four fundamental forces in nature


  True
• The strong nuclear force overcomes the electrostatic repulsion between protons.
• What is the nucleon ratio also known as?

  Proton-to-neutron ratio
• What happens to a nucleus when it deviates from the line of stability?

  Radioactive decay
• Gamma decay changes the atomic number of the nucleus.

  False
• What is the role of the strong nuclear force?

  Holds protons and neutrons together
• What is the process called when two light nuclei combine to form a heavier nucleus?

  Fusion
• In a nuclear reaction called fusion, two or more lighter nuclei combine to form a heavier nucleus
• What is the term for the process where one element changes into another due to nuclear reactions?

  Nuclear transmutation
• Classify the types of nuclear reactions based on their energy change from largest to smallest.

  1️⃣ Fusion

  2️⃣ Fission

  3️⃣ Radioactive decay
• The remaining mass of a radioactive material after time t can be calculated using the formula N(t) = N₀ * e^(-λt).


  True
• Match the radioactive dating technique with its corresponding radioactive isotope and half-life:

  Carbon Dating ↔️ Carbon-14 (5,730 years)

  Uranium-Lead Dating ↔️ Uranium-238 (4.5 billion years)

  Potassium-Argon Dating ↔️ Potassium-40 (1.3 billion years)
• What is nuclear instability caused by?

  Imbalanced proton-to-neutron ratio