Atomic Structure

• What are 3 sub-atomic particles?

  proton & electron & neutron
• What is the mass of an electron?

  1/1840
• What letter represents mass?

  m
• What letter represents atomic number?

  z
• How are positive ions former?

  losing an electron
• Isotope definition?

  atom with the same number of protons but a different number of neutrons
• Why do isotopes have the same chemical properties?

  same number of electrons
• What was JJ Thompson Model?

  plum pudding model - sphere with positive charge with electrons dotted around
• Describe the Rutherford experiment for the discovery of the atomic nucleus?

  fired alpha particles at gold foil, some deflected and some flew bounced back showing a small centre of positive charge
• Describe Bohr model?

  electrons in defined shells orbiting a positive nucleus
• How could you calculate the mass of an atom (eg. O)?

  Ar/Avogadro constant
• What is the definition of of relative atomic mass?

  Mean mass of atoms from an element relative to the mass of 12g of carbon 12
• How many electrons can the s orbital hold?

  2
• How many electrons can the p orbital hold?

  6
• How many electrons can the d orbital hold?

  10
• Which two transition metals do not have 4 orbital?

  chromium & copper
• Which energy levels do electrons fill first?

  lowest energy levels to higher energy levels
• What is the definition of first ionisation energy?

  energy required to remove one mole of electrons from one mole of atoms in the gaseous state
• Is ionisation energy exothermic or endothermic?

  endothermic
• What are the 4 main stages in mass spectrometer?

  ionisation & acceleration & deflection & detection
• What is a generic equation to show the ionisation that could be used in a Mass Spectrometer?

  x (g) --> x+(g) + e-
• What are two methods of ionisation that could be used in mass spectrometer?

  electrospray & electron impact
• What is the generic equation to show electrospray?

  x (g) + H+ --> xH+ (g)
• What occurs during Mass Spectrometry electrospray ionisation?

  Dissolved in a volatile solvent, high pressure through charge needle ; Particles gain a proton
• What occurs during Mass Spectrometry acceleration?

  elements enter electric field causing to accelerate ; having the same kinetic energy
• What occurs during Mass Spectrometry drift?

  ions with different masses have different times of flights ; lighter ions faster the ions reach the detector
• What occurs during Mass Spectrometry detection?

  detector is negatively charged plate ; current produced when ion shit plate, more ions that hit detector = higher current
• What is molecular ion peak?

  highest m/z value on the spectrum of a molecule, forming when molecule does not break up
• What is a m/z value?

  mass-to-charge ratio
• How does nuclear charge affect ionisation energy?

  increase nuclear charge increase ionisation energy as electrons become harder to remove
• How does 1st ionisation energy change down the group?

  decreases down the group
• Why does 1st ionisation energy change down the group?

  electrons further from nucleus so less attraction & more shielding so less attraction
• Write an equation to show the 3rd ionisation energy of an element?

  x2+ --> x3 + e-
• Why do group 3 elements not fit the trend of ionisation energy across the period?

  electrons removed from p orbital which is further from the nucleus so less attraction leading to ionisation energy decreasing
• Why do group 6 elements not fit the trend in ionisation energy across the period?

  Electrons removed from orbital with spin pairing gives some repulsion so it is easier to remove ; ionisation energy decreases