Nuclear Reactions Notes

Nuclear Reactions

  • Occur in the nucleus, forming new atoms.
  • Involve changes to protons and neutrons within the nucleus.

Radioactive Decay

  • Spontaneous breakdown of a nucleus by emitting radiation.
  • Represented by nuclear equations.

Nuclear Equations

  • Reactants: Radioactive nucleus.
  • Products: New nucleus and radiation particle.
  • Balanced by conserving mass numbers and atomic numbers on both sides.

Alpha Decay

  • Alpha particle: α=24He\alpha = {}^{4}_{2}He
  • Example: Uranium decay 238<em>92U→234</em>90Th+24He{}^{238}<em>{92}U \rightarrow {}^{234}</em>{90}Th + {}^{4}_{2}He
  • Smoke detectors utilize Americium-241, which decays by alpha emission, ionizing air and creating a current. Smoke disrupts the current, triggering the alarm.

Beta Decay

  • A neutron in the nucleus converts into a proton and emits an electron (beta particle).
  • Example: Carbon-14 decay 14<em>6C→14</em>7N+−10e{}^{14}<em>{6}C \rightarrow {}^{14}</em>{7}N + {}^{0}_{-1}e

Positron Emission

  • A proton in the nucleus converts into a neutron, emitting a positron (positive electron).
  • Positron: +10e{}^{0}_{+1}e
  • Example: Manganese-49 decay 49<em>25Mn→49</em>24Cr++10e{}^{49}<em>{25}Mn \rightarrow {}^{49}</em>{24}Cr + {}^{0}_{+1}e

Gamma Radiation

  • Emission of energy; no change in mass number or atomic number.
  • Does not alter the identity of the species.

Synthetic Reactions

  • Man-made reactions where a stable nucleus is bombarded with a particle.
  • Used to create elements with atomic numbers greater than 92 (transuranic elements).
  • Example: Bombarding Boron-10 with alpha particles to produce a radioactive nucleus.

Balancing Nuclear Equations

  • Ensure the sum of mass numbers and atomic numbers are equal on both sides of the equation.