Chapter 8, Problem 31b
(b) A substance, XY, formed from two different elements, melts at −33 °C. Is XY likely to be a covalent or an ionic substance?
Video transcript
List the individual steps used in constructing a Born–Haber cycle for the formation of BaI2 from the elements. Which of the steps would you expect to be exothermic?
(a) Based on the lattice energies of MgCl2 and SrCl2 given in Table 8.1, what is the range of values that you would expect for the lattice energy of CaCl2?
(b) Using data from Appendix C, Figure 7.11, Figure 7.13, and the value of the second ionization energy for Ca, 1145 kJ/mol, calculate the lattice energy of CaCl2.
Using Lewis symbols and Lewis structures, make a sketch of the formation of NCl3 from N and Cl atoms, showing valence-shell electrons. (e) How many lone pairs of electrons are in the NCl3 molecule?
Using Lewis symbols and Lewis structures, diagram the formation of PF3 from P and F atoms, showing valence-shell electrons. (c) How many valence electrons surround the P in the PF3 molecule?
Using Lewis symbols and Lewis structures, diagram the formation of PF3 from P and F atoms, showing valence-shell electrons. (e) Does PF3 obey the octet rule?