Ionisation energies

• What is the first ionisation energy?

  The minimum amount of energy required to remove one mole of electron from an atom in its gaseous state.
• What is the P-block?

  It is where the last electron enters one of the three P orbitals of their shells
• What is the S block?

  It is where the last electron enters the S orbital of their shells
• What are the three factors that affect ionisation energy?

  Atomic radius, Nuclear charge, Electron Sheilding
• What does it mean if there is a large jump in ionisation energies?

  It means that the electron is being removed from a different orbital
• What is atomic radius?

  It is the distance between the nucleus and outer electrons, the greater the distance the lower the forces of attraction
• What is nuclear charge?

  It is the number of protons in the nucleus, the greater the nuclear charge the greater the attraction between the outer electrons therefore meaning a higher ionisation energt
• Ionisation energies equations?


  He(g)--> He+(g)+e-
• Second ionisation energies equations?

  He+(g)->He2+(g)+e-
• Trends across a period?

  • nuclear charge increases
  • Similar shielding
  • Nuclear attraction increases
  • Atomic radius decreases
  • FIE increases
• Trends in FIE down a group?

  • Atomic radius increases
  • more inner shells so sheilding increases
  • Nuclear attraction decreases
  • FIE decreases