Using data from Appendix 8, construct a graph to show the trend in the third ionization energies of the elements from Li to Kr. Compare the graph with that shown in Fig. 1.16, and rationalize what you observe.

Figure 1.16

Data from Appendix 8

Data are given for the first five ionizations.† IE(n) in kJ mol⁻¹ for the processes:

First ionization energy, IE/kJ mol 2500 2000- 1500- 1000- 500- He H 0 Be Li Ne Mg Na 10 Al 20 Zr As Ge 30 Kr Se Rb 40 Cd In - 50 Xe 60 70 Hg T 80 Rn 90 N