AP10

• What is the relative mass of an electron?

  1/2000 or negligible
• What is the overall charge of an atom?

  Neutral or zero
• What is the overall charge of a nucleus?

  Positive
• What is the approximate size of an atom?

  1 x 10^-10 m
• What is the approximate size of a nucleus?

  1 x 10^-15 m
• What is found between the nucleus and electrons?

  Empty space
• In A-Z nuclide notation, what does A represent?

  Nucleon number

  
• In A-Z nuclide notation, what does Z represent?

  Proton number / atomic number

  
• Which number, A or Z, defines which element it is?

  Z (proton/atomic number)
• What is the definition of nucleon number?

  Total number of protons and neutrons
• What happens when photons of EM radiation hit a metal surface?

  Photoelectrons are emitted from the surface.
• Atoms have equal numbers of what two particles?

  Protons and electrons
• How does a photon transfer energy in the photoelectric effect?

  One photon transfers all its energy to one electron.
• What is the range of kinetic energies of emitted photoelectrons?

  From 0 up to a maximum value.
• What determines the maximum kinetic energy of photoelectrons?

  The frequency of the radiation determines it.
• What is the work function (φ)?

  The minimum photon energy required for emission.
• What is the magnitude of the charge on an electron/proton?

  1.60 x 10^-19 C
• What is the threshold frequency (fo)?

  The minimum frequency required for emission.
• How is work function related to threshold frequency?

  φ = hfo links them together.
• What is the mass of a nucleon?

  1.67 x 10^-27 kg
• How do frequency and work function relate to maximum kinetic energy?

  hf = φ + Ek(max) describes the relationship.
• What is the mass of an electron?

  9.11 x 10^-31 kg
• What happens to photon energy when frequency increases?

  Photon energy increases as frequency increases.
• How does increasing intensity affect the photoelectric effect?

  More photons incident per second increase emission.
• How do we work out the mass of an atom, ion or nucleus in kilograms?

  Number of nucleons x 1.67 x 10^-27
• What is stopping potential?

  The potential difference to stop electron emission.
• What is the equation for stopping potential?

  Vs = Ek(max) / e describes it.
• How do we work out the charge of a nucleus in coulombs?

  Number of protons x 1.60 x 10^-19
• What is the ground state of an electron?

  Lowest energy level (n=1) closest to nucleus.
• How do we work out the charge of an ion in coulombs?

  Relative charge x 1.60 x 10^-19
• What is excitation in terms of energy levels?

  An electron moves to a higher energy level.
• How do we calculate specific charge?

  Specific charge = charge / mass = Q / m
• How can electrons gain energy to become excited?

  By photon transfer or electron collision.
• What are the units for specific charge?

  C kg^-1
• What is de-excitation in terms of energy levels?

  An electron moves to a lower energy level by emitting a photon.
• What are isotopes?

  Atoms with the same number of protons and different numbers of neutrons
• What is ionization?

  An electron gains enough energy to be removed.
• Do isotopes have different chemical properties?

  False
• What is ionization energy?

  The energy required to remove an electron completely.
• Do isotopes have different nuclear stability?

  True