Ionisation energy

• X(g)


  Gaseous atom
• X+

  (g)

  Gaseous uni-positive ion
• X2+

  (g)

  Gaseous di-positive ion
• Ionisation Energy (Hi)


  Energy required to knock out a mole of electrons from a mole of atoms/ions

  
• First Ionisation Energy (Hi1)

  Energy required to remove a mole of electrons from a mole of gaseous atoms to form uni-positive ions

  
• Second Ionisation Energy (Hi2)


  Energy required to remove a mole of electrons from a mole of gaseous uni-positive ions to form di-positive ions

  
• As more electrons are removed

  The proton to electron ratio increases and there is an increasing attraction for the remaining electrons from the nucleus, hence the ionisation energies increase

  
• Principal quantum number (n)


  Indicates the shell
• Sub-shells


  • s
  • p
  • d
  • f
• s orbitals


  • Spherical shape
• p orbitals


  • 'Figure of eight' shape, 3 orbitals make up the sub-shell
• d sub-shells


  • More complex shape
• Magnetic quantum number indicates which orbital an electron is in. The p sub-shell has three orbitals: Px, Py and Pz. These are mutually at right angles. The d sub-shell is made up of 5 orbitals.
• Box notation


  Involves all 4 quantum numbers
• Orbital


  A region outside the nucleus in which an electron can be found, can hold a maximum of two electrons of opposite spin
• Magnetic quantum number


  Indicates which orbital an electron is in
• Spin quantum number


  Indicates the spin of the electron (clockwise or anti-clockwise)