Ionisation energies and shells

1)    a)  Define the 1^st ionisation energy and write the equation for Bromine [4]

        The energy required to remove one electron from each atom [1] in 1 mole of gaseous atoms [1] to form 1 mole of gaseous 1+ ions [1]

        Br_(g)             à        Br⁺_(g)        +          e^-     [1]

       b)  Write equations including state symbols to represent the:

                i)   1^st ionisation energy of Li                Li_(g)             à        Li⁺_(g)        +          e^-     [1]

                ii)  3^rd ionisation energy of Al                Al²⁺ _(g)             à        Al³⁺_(g)        +          e^-      [1]

            Use the symbol e- to represent electrons [2]

       c)  What would you notice about the next ionisation energy for (i) and (ii)?  Explain your answer using atomic structure. [7]

                i)   2^nd ionisation energy of Li would have a significant increase as you move to an inner electron shell. [1]

                     Due to less shielding [1] as fewer inner shells, electron is closer to the nucleus so greater attraction [1]         

                ii)  3^rd ionisation energy of Al would show a slight increase as electron is removed from the same electron shell. [1]

                     Due to higher proton : electron ratio [1] increasing attraction of remaining electrons [1].  Shielding is the same. [1]

2)    How does the 1^st ionisation energy change down group 2 and explain why? [3]

As you go down a Group, the outer electron shell is further from the nucleus - attraction decreases. [1]

The more inner shells the greater the shielding. [1]

As you go down Group 2, ionisation energy decreases. [1]

3)    Sketch the graph for the successive ionisation energies for Na [3]

                        Large jump between 1st and 2nd [1]  general increase for 2 - 9 [1]  large jump between 9 and 10 [1]

4)    The successive ionisation energies are shown:

        a)  To which group of the periodic table does this element belong? Explain your answer. [2]

                        Group 4 [1]  as there is a large jump between IE 4 and 5 [1]

        b)  This element is in Period 2, identify the element. Explain your answer.  [3]

                        Carbon [1]  as it is in Group 4 from the large jump between IE 4 and 5 [1]  Group 4 element in Gp2 is carbon [1]