Problem 25
When comparing the size of different ions, the general radii trend discussed in Chapter 7 is usually not very useful. What do you concentrate on when comparing sizes of ions to each other or when comparing the size of an ion to its neutral atom?
Problem 26
In general, the higher the charge on the ions in an ionic compound, the more favorable the lattice energy. Why do some stable ionic compounds have \(+1\) charged ions even though \(+4,+5,\) and \(+6\) charged ions would have a more favorable lattice energy?
Problem 27
Combustion reactions of fossil fuels provide most of the energy needs of the world. Why are combustion reactions of fossil fuels so exothermic?
Problem 28
Which of the following statements is(are) true? Correct the false statements. a. It is impossible to satisfy the octet rule for all atoms in \(\mathrm{XeF}_{2}\) . b. Because \(\mathrm{SF}_{4}\) exists, OF_ should also exist because oxygen is in the same family as sulfur. c. The bond in NO + should be stronger than the bond in \(\mathrm{NO}^{-}\). d. As predicted from the two Lewis structures for ozone, one oxygen-oxygen bond is stronger than the other oxygen-oxygen bond.
Problem 29
Use formal charge arguments to explain why CO has a much smaller dipole moment than would be expected on the basis of electronegativity
Problem 30
The molecules \(\mathrm{BF}_{3}, \mathrm{CF}_{4}, \mathrm{CO}_{2}, \mathrm{PF}_{5},\) and \(\mathrm{SF}_{6}\) are all nonpolar, even though they contain polar bonds. Why?
Problem 31
Without using Fig. 8.3, predict the order of increasing electronegativity in each of the following groups of elements. a. \(\mathrm{C}, \mathrm{N}, \mathrm{O} \quad\) c. \(\mathrm{Si}, \mathrm{Ge}, \mathrm{Sn}\) b. \(\mathrm{S}, \mathrm{Se}, \mathrm{Cl} \quad\) d. \(\mathrm{TI}, \mathrm{S}, \mathrm{Ge}\)
Problem 32
Without using Fig. 8.3, predict the order of increasing electronegativity in each of the following groups of elements. a. \(\mathrm{Na}, \mathrm{K}, \mathrm{Rb} \quad\) c. \(\mathrm{F}, \mathrm{Cl}, \mathrm{Br}\) b. \(\mathrm{B}, \mathrm{O}, \mathrm{Ga} \qquad\) d. \(\mathrm{S}, \mathrm{O}, \mathrm{F}\)
Problem 33
Without using Fig. 8.3, predict which bond in each of the following groups will be the most polar. a. \(\mathrm{C}-\mathrm{F}, \mathrm{Si}-\mathrm{F}, \mathrm{Ge}-\mathrm{F} \quad\) c. \(\mathrm{S}-\mathrm{F}, \mathrm{S}-\mathrm{Cl}, \mathrm{S}-\mathrm{Br}\) b. \(\mathrm{P}-\mathrm{Cl}\) or \(\mathrm{S}-\mathrm{Cl} \quad\) d. \(\mathrm{Ti}-\mathrm{Cl}, \mathrm{Si}-\mathrm{Cl}, \mathrm{Ge}-\mathrm{Cl}\)
Problem 34
Without using Fig. 8.3, predict which bond in each of the following groups will be the most polar. a. \(\mathrm{C}-\mathrm{H}, \mathrm{Si}-\mathrm{H}, \mathrm{Sn}-\mathrm{H}\) b. \(\mathrm{Al}-\mathrm{Br}, \mathrm{Ga}-\mathrm{Br}, \mathrm{In}-\mathrm{Br}, \mathrm{Tl}-\mathrm{Br}\) c.\(\mathrm{C}-\mathrm{O}\) or \(\mathrm{Si}-\mathrm{O}\) d. \(\mathrm{O}-\mathrm{F}\) or \(\mathrm{O}-\mathrm{Cl}\)
