7. The lattice enthalpy values for lithium fluoride and calcium fluoride are shown below.
ï = +1022 kJ mol−1
ï = +2602 kJ mol−1
Which of the following statements help(s) to explain why the value for lithium fluoride is less than that for calcium fluoride?
I. The ionic radius of lithium is less than that of calcium.
II. The ionic charge of lithium is less than that of calcium.