From the ionic radii given in Figure 7.7, calculate the potential energy of a Ca2+ and O2- ion pair that is just touching (the magnitude of the electronic charge is given on the back inside cover). Calculate the energy of a mole of such pairs. How does this value compare with the lattice energy of CaO (Table 8.2)? Explain the difference.

Transcribed Image Text:

Group 1A Group 2A Group 3A roup 6A Group 7A 0.90 0.41 1.34 0.90 0.82 0.73 0.71 0.86 0.68 1.70 1.54 1.30 0.99 1.52 1.14 0.76 1.82 1.96 1.24 1.26 1.66 0.94 2.06 2.11 2 144 1.33 - cation anion neutral atom TABLE 8.2 Lattice Energes for Some Ionic Compounds Lattice Energy (kJ/mol) Lattice Energy Compound LiF LiCl Lil NaF NaCI NaBr Nal KF KCI KBr CsCl CsI Compound (kJ/mol) MgCl2 SrCl 1030 834 730 910 788 732 682 808 701 671 657 600 2326 2127 Mgo CaO SrO 3795 3414 3217 SCN 7547