Particle Physics

• What is the center of an atom called?

  The nucleus
• What is contained in the nucleus of an atom?

  Nucleons (protons and neutrons)
• What is the diameter of the nucleus?

  $10^{-15} \text{ m} \text{ (1 fm)}$
• What is the diameter of an atom?

  $10^{-10} \text{ m} \text{ (100,000 times the nucleus diameter)}$
• What is the charge of a proton?

  $1.6 \times 10^{-19} \text{ C}$
• What is the mass of a neutron?

  $1.67 \times 10^{-27} \text{ kg}$
• What is the relative mass of an electron?

  0.0005
• What is the relative charge of a neutron?

  0
• What is the equation for specific charge?

  Specific charge = charge / mass
• What are the units for specific charge?

  $C \cdot kg^{-1}$
• What is an isotope?

  Atoms with the same number of protons and electrons but different numbers of neutrons
• What is the isotope notation?

  $_Z^AX$
• In the isotope notation $_Z^AX$, what does A represent?


  A represents the mass number
• In the isotope notation $_Z^AX$, what does Z represent?


  Z represents the proton number
• In the isotope notation $_Z^AX$, what does X represent?


  X represents the chemical symbol of the element
• What are the properties of protons, neutrons, and electrons?

  • Proton:
  • Charge: $1.6 \times 10^{-19} \text{ C}$
  • Mass: $1.67 \times 10^{-27} \text{ kg}$
  • Relative mass: 1
  • Relative charge: 1
  • Neutron:
  • Charge: 0
  • Mass: $1.67 \times 10^{-27} \text{ kg}$
  • Relative mass: 1
  • Relative charge: 0
  • Electron:
  • Charge: $-1.6 \times 10^{-19} \text{ C}$
  • Mass: $9.11 \times 10^{-31} \text{ kg}$
  • Relative mass: 0.0005
  • Relative charge: -1
• What are the three constituents of an atom?

  Protons, neutrons, and electrons
• Where are protons and neutrons located in an atom?

  In the nucleus at the center of the atom
• What are protons and neutrons collectively known as?

  Nucleons
• How do electrons move in relation to the nucleus?

  Electrons orbit the nucleus in shells
• What is specific charge and how is it calculated?

  Specific charge is the charge-mass ratio calculated by dividing a particle's charge by its mass

  
• What is the specific charge of a proton?

  $9.58 \times 10^7 \text{ Ckg}^{-1}$
• What does the proton number (Z) represent?

  The number of protons in an atom
• What does the nucleon number (A) represent?

  The total number of protons and neutrons in an atom
• What are isotopes?

  Atoms with the same number of protons but different numbers of neutrons
• How is carbon-14 used in carbon dating?

  By calculating the percentage of carbon-14 remaining in an object
• What is the strong nuclear force (SNF)?

  A force that keeps nuclei stable by counteracting the electrostatic force of repulsion between protons
• What happens to unstable nuclei?

  They decay to become stable
• What is alpha decay?

  A decay process where the proton number decreases by 2 and the nucleon number decreases by 4
• What is beta-minus decay?

  A decay process that occurs in neutron-rich nuclei where the proton number increases by 1
• Why were neutrinos hypothesized during beta-minus decay?

  To account for the missing energy in the decay process
• What is an antiparticle?

  A particle that has the same rest energy and mass but opposite properties
• What is a photon?

  A packet of electromagnetic radiation that transfers energy and has no mass
• How is the energy of a photon related to its frequency?

  The energy of photons is directly proportional to the frequency of electromagnetic radiation
• What is the equation for the energy of a photon?

  $E =$$hf$
• What occurs during annihilation?

  A particle and its antiparticle collide, converting their masses into energy
• How does a PET scanner utilize annihilation?

  By introducing a positron-emitting radioisotope that annihilates with electrons, emitting gamma photons
• What is pair production?

  The conversion of a photon into an equal amount of matter and antimatter

  
• What are the four fundamental forces?

  Gravity, electromagnetic, weak nuclear, and strong nuclear
• What are exchange particles?

  Particles that carry energy and momentum between particles experiencing a force