15.3 Nuclear Physics

• Match the atomic component with its charge:

  Protons ↔️ Positive

  Neutrons ↔️ Neutral

  Electrons ↔️ Negative
• What does Z represent in atomic notation?

  Atomic number
• Which nuclear force holds protons and neutrons together in the nucleus?

  Strong nuclear force
• What particle is emitted during alpha decay?

  Alpha particle
• Match the nuclear force with its role:

  Strong Nuclear Force ↔️ Holds the nucleus together

  Weak Nuclear Force ↔️ Governs radioactive decay
• The strong nuclear force holds the nucleus together, while the weak nuclear force governs radioactive decay
• The strong nuclear force is the strongest force in nature
• Order the steps in alpha decay:

  1️⃣ Uranium-238 nucleus

  2️⃣ Alpha particle emitted

  3️⃣ Thorium-234 nucleus
• The half-life is the time required for half of the radioactive nuclei in a sample to decay.
• The formula relating half-life and decay constant is $T_{1 / 2} =$$\frac{\ln 2}{λ}$, where \( T_{1/2} \) is the half-life and \( λ \) is the decay constant.
• Nuclear fission is the process in which a heavy nucleus splits into two or more smaller nuclei.
• A chain reaction is a self-sustaining sequence of nuclear fission events.
• What are the products of the fission of uranium-235 after absorbing a neutron?

  Ba-141, Kr-92, 3n
• A chain reaction in nuclear fission is self-sustaining because it releases neutrons that trigger further fission events.

  True
• Which process powers the Sun and other stars?

  Nuclear fusion
• What two forces determine nuclear stability?

  Strong nuclear and electrostatic repulsion
• What determines the stability of an atomic nucleus?

  Strong nuclear force
• What is the formula to calculate binding energy per nucleon?

  $B / A =$$\frac{M_{N}(Z,N) - M}{A}$
• Arrange the subatomic particles based on their charge and location:

  1️⃣ Protons: Positive charge, nucleus

  2️⃣ Neutrons: Neutral charge, nucleus

  3️⃣ Electrons: Negative charge, orbiting the nucleus
• Match the term in atomic notation with its definition:

  A ↔️ Mass number

  Z ↔️ Atomic number

  X ↔️ Element symbol
• The weak nuclear force is responsible for beta decay.


  True
• What happens to the mass number and atomic number during alpha decay?

  Mass number decreases by 4, atomic number decreases by 2
• Gamma decay involves the emission of a gamma photon
• The strong nuclear force holds the nucleus together, while the weak nuclear force governs certain types of radioactive decay
• The half-life and decay constant are inversely related.


  True
• Nuclear fission involves the splitting of a heavy nucleus into two or more lighter nuclei
• Nuclear fission is used in nuclear power plants to generate electricity
• The number of protons in an atom determines its element

  True
• Isotopes of the same element have the same number of protons but different numbers of neutrons


  True
• The weak nuclear force is responsible for certain types of radioactive decay
• Beta decay involves the emission of an electron or a positron
• What does the weak nuclear force govern?

  Radioactive decay
• What is the approximate range of the strong nuclear force?

  10^{-15} meters
• What particles are emitted during beta decay?

  Electron or positron
• What changes occur in the nucleus during beta decay?

  Neutron-proton balance
• What does the decay constant represent?

  Probability of decay
• What is the decay constant of radium-226 if its half-life is 1600 years?

  1.37 x 10^{-11} s^{-1}
• What is a chain reaction in nuclear fission?

  Self-sustaining sequence
• What type of nuclei are used in nuclear fission?

  Heavy nuclei
• Which nuclear reaction releases more energy: fusion or fission?

  Fusion