Atomic Structure

• Formula for number of electrons in each energy level?

  2n^2
• What is the definition of an atomic orbital?

  the region around the nucleus which can hold up to 2 electrons with opposite spin
• What is an electron?

  cloud of negative charge
• What are the 4 letters of the atomic orbitals?

  s p d f
• What is the shape of a S-orbital?

  spherical
• What is the shape of a P-orbital?

  dumbell
• 2 elements that are exceptions when working out electronic configuration?

  chromium and copper
• What is the definition of first ionisation energy?

  energy needed to remove one mole of electrons from one mole of atoms in their gaseous state to form one mole of 1+ ions ( also in their gaseous state)
• What is the definition of second ionisation energy?

  energy needed to remove one mole of electrons from one mole of 1+ ions in their gaseous state to form one mole of 2+ ions ( also in their gaseous state)
• What happens to first ionisation energy as you go down a group?

  decreases
• List the scientists involved in development of atom?

  Dalton

  thomson

  rutherford

  bohr

  schrodinger

  chadwick
• What was Schrodingers theory?

  electrons behaved as a wave and particle
• What is the atomic mass unit defined as?

  1/12 of the mass of Carbon 12
• What is the symbol for atomic number?

  Z
• What is the formula for Mass Number?

  A
• What is the first step of mass spectroscopy?

  ionisation
• What are the 2 ways to ionise a sample in mass spectroscopy?

  electron impact

  electrospray
• How does electron impact ionise atoms?

  fire high energy electrons at vaporised atoms knocking electrons off and creating positive ions
• What state must the atoms be in to become ionised by electron impact?

  gas
• How does electrospray ionise a sample?

  sample dissolved in a volatile solvent that can be a source of H+ ions and this is injected into the spectrometer through a fine needle with a high voltage producing a fine mist which produces positive ions through adding a hydrogen ion
• Explain why it is necessary to ionise molecules when measuring their mass in a TOF mass spectrometer?

  ions not molecules will interact with and be accelerated by an electric field

  only ions will generate current when hitting the detector
• Define the term relative atomic mass?

  mean mass of one atom of an element

  1/12 mass of one atom of carbon 12
• What happens in the acceleration stage in Mass Spectrometry?

  the gaseous positive ions are accelerated due to the interaction with an electric field which gives them all the same kinetic energy
• What is Time of Flight in mass spectrometry?

  the ions move into a tube under a high vacuum and the lightest ions will move faster than the heavier ions
• What happens in detection in mass spectrometry?

  ions hit the detector which induces a current
• Explain how ions are accelerated, detected and have their abundance determined in time of flight?

  Ions accelerated by attraction to electric field

  Ions detected by gaining electrons

  abundance detected by current flowing in the detector
• What 3 factors affect ionisation energy?

  nuclear charge

  shielding

  distance
• Why does ionisation energy increase when nuclear charge increases?

  stronger attraction between nucleus and electron
• What is shielding?

  inner shells of electrons repel the outer electrons
• Why does oxygen have a lower 1st ionisation energy than nitrogen?

  electrons have paired up in the 2p orbital
• Why is there little variation in the ionisation energies of the D block?

  electrons empty from 4s subshell first
• Why does the second ionisation energy of each element increase?

  electron being removed from a positive ion
• State in terms of electrons, the meanining of oxidising agent?

  Electron acceptor