EL8

• The s-block contains the elements in groups 1 and 2
• The elements in groups 1 and 2 become more metallic as you go down the group. This is why the most reactive elements are found at the bottom of the groups
• The elements become less metallic across the period. This is why group 1 elements are more reactive than group 2 elements
• The first ionisation enthalpy is where the electron is removed from the outer shell of the atom
• The first ionisation enthalpy is the energy required to remove one mole of electrons from one mole of gaseous atoms
• The general equation for the first ionisation process is: X(g) → X+(g) + e-
• The peaks of ionisation energy is at the group 0 elements as they are very hard to ionise due to their low reactivity

  
• Going down a group in the periodic table, the first ionisation enthalpies decrease, this is due to the attraction between the outer electrons and the nucleus decreasing
• Successive ionisation enthalpies: more than one element can be removed from an atom (except hydrogen).

  The removal of any subsequent electrons involves the removal of an electron from a positive ion - it is not the energy required to remove +1 electron from the atom

  
• The trends with the group 2 compounds