Which of the following elements cannot have an expanded octet? (More than 8 valence electrons). a. Br b. O c. Xe d. P e. S

rite the Lewis structure for each of the following atoms. msp;a.He(Z=2)d.Ne(Z=10)b.Br(Z=35)e.I(Z=53)c.Sr(Z=38)f.Ra(Z=88)

Which statement(s) is/are true about bond enthalpy? (a) The bond energy for a triple bond between A and B is three times that of a single bond between A and B. (b) H for the breaking of a bond is always a negative number. (c) Energy is required to make a bond. (d) Bond enthalpy is defined only for bonds broken or formed in the gaseous state. (e) The presence of bonds does not influence the geometry of a molecule. However, the presence of bonds affects the value of the bond enthalpy between two atoms.

Compare your answers from parts a and b of Exercise 69 of Chapter 3 with H values calculated for each reaction using standard enthalpies of formation in Appendix 4. Do enthalpy changes calculated from bond energies give a reasonable estimate of the actual values?