Amount of substance

• What charge do protons have?

  Positive charge
• What is the charge of neutrons?

  Zero charge
• What is the charge of electrons?

  Negative charge
• What is the relative mass of an electron?

  1/2000
• What does the top number in an element's notation represent?

  Mass number (protons + neutrons)
• What does the bottom number in an element's notation represent?

  Atomic number (number of protons)
• Why are all atoms neutral?

  Protons equal electrons in number
• What defines an ion?

  Different number of electrons and protons
• What is the charge of the O2- ion?

  Minus two charge
• How many protons does O2- have?

  Eight protons
• How many electrons does O2- have?

  Ten electrons
• What is the charge of a sodium ion (Na+)?

  Plus one charge
• How many protons does sodium have?

  Eleven protons
• How many electrons does Na+ have?

  Ten electrons
• What are isotopes?

  Same protons, different neutrons
• What are the three isotopes of carbon mentioned?

  Carbon-12, Carbon-13, Carbon-14
• How do isotopes of an element behave chemically?

  They react the same due to electrons
• What is the time of flight mass spectrometer used for?

  To analyze the mass of ions
• What is the first step in mass spectrometry?


  Vaporization of the sample
• What is electrospray ionization?

  Turning a sample into gaseous ions
• What happens during the acceleration stage in mass spectrometry?

  Particles are accelerated by electric fields
• What is the ion drift stage in mass spectrometry?

  Particles travel at constant speed
• What occurs during the detection stage in mass spectrometry?

  Electrical current is generated upon impact
• What is relative atomic mass?

  Average mass of an atom compared to carbon-12
• What is relative molecular mass?

  Average mass of a molecule compared to carbon-12
• What is relative isotopic mass?

  Mass of an isotope compared to carbon-12
• What does the x-axis represent in a mass spectrum?

  Mass-to-charge ratio of isotopes
• What does the y-axis represent in a mass spectrum?

  Abundance of isotopes
• What must the total abundance of isotopes equal?

  100 percent
• How can isotopes be identified in a mass spectrum?

  By their mass-to-charge ratio
• What does a higher mass-to-charge ratio indicate?

  Heavier isotopes in the sample
• What is the significance of the abundance in a mass spectrum?

  It shows the relative amount of isotopes
• What are the key points of atomic structure according to AQA specification?

  • Composition of atoms: protons, neutrons, electrons
  • Charges of subatomic particles
  • Mass numbers and atomic numbers
  • Differences between ions and isotopes
  • Historical models of the atom
  • Mass spectrometry principles
• What are the historical developments in atomic theory?

  1. John Dalton: Atoms as solid spheres
  2. JJ Thompson: Plum pudding model
  3. Ernest Rutherford: Nucleus discovery
  4. Neil's Bohr: Fixed energy levels
• What are the steps in mass spectrometry?

  1. Vaporization of the sample
  2. Ionization (electrospray)
  3. Acceleration by electric fields
  4. Ion drift at constant speed
  5. Detection of ions
• What are the definitions related to atomic mass?

  • Relative atomic mass: Average mass of an atom compared to carbon-12
  • Relative molecular mass: Average mass of a molecule compared to carbon-12
  • Relative isotopic mass: Mass of an isotope compared to carbon-12
• What happens to the mass-to-charge ratio if two electrons are knocked off?

  It becomes half as much
• What does the symbol Z represent in mass-to-charge ratio?

  It stands for charge
• What is the maximum percentage abundance of isotopes?

  100%
• How can isotopes' abundance be represented?

  As a percentage or nominal value