Section 7.4 to 7.8
1. Define ionization energy
2. What is the trend in ionization energies?
3. Referring to the periodic table, arrange the atoms Ne, Na, P, Ar, K in order of increasing first ionization
energy.
4. Why is it easier to remove an electron from a 2p electron from oxygen than it is for nitrogen?
5. Consider the following statements about first ionization energies:
a. Because the effective nuclear charge for Mg is greater than that for Be, the first ionization energy of
Mg is greater than that of Be.
b. The first ionization energy of O is less than that of N because in O we must pair electrons in the 2p
orbitals.
c. The first ionization energy of Ar is less than that of Ne because a 3p electron in Ar is farther from
the nucleus than a 2p electron in Ne.
6. What does the electron configuration of chlorine vs the chloride ion look like? Why do ions form the way
that they do? What is the driving factor for their formation?
7. Define electron affinity.
8. What is the difference in ionization energy and electron affinity?
9. Define metallic character
10. List the properties of metals and nonmetals
11. Metals tend to have high or low ionization energies. What about nonmetals?
12. Compounds between metals and nonmetals tend to form ionic/covalent compounds?
13. Most metal oxide bonds are basic/acidic.
14. Would you expect scandium oxide to be a solid, liquid, or gas at room temperature?
a. Write the balanced chemical equation for the reaction of scandium oxide with nitric acid.
15. Nobel gases exhibit what for each of the following: ionization energy, electron affinity, electronegativity.
16. Nonmetal to nonmetal compounds form what type of bonds.
17. Most nonmetal oxides are acidic or basic?
18. Write a balanced chemical equation for the reaction of solid selenium dioxide, SeO21s2, with (a) water, (b)
aqueous sodium hydroxide.
19. What characteristics do metalloids exhibit?
20. What are the names of group 1A and 2A metals?
21. What is a hydride ion and how are they formed?
22. What is the general reaction for alkali metals with water?
23. What is the melting point trend in alkali metals?
24. What is the most reactive alkali metal? The least?
25. Write a balanced equation for the reaction of cesium metal with (a) Cl2(g), (b) H2O(l), (c) H2(g).
26. Write a balanced equation for the expected reaction between potassium metal and elemental sulfur, S(s).
27. What is the reactions of group 2A metals with water?
28. What is ozone?
29. Define allotrope.
30. Can hydrogen form both ionic and covalent (molecular) bonds? If so, give example of both.
31. Define halogens. (describe their natural state as well)
32. Speculate as to why halogens do not exist in X8 like sulfur and selenium.
33. Do halogens react with metal directly? If so, give a general formula.
34. Describe noble gases.
35. What makes noble gases so noble?
36. The element bismuth (Bi, atomic number 83) is the heaviest member of group 5A. A salt of the element,
bismuth subsalicylate, is the active ingredient in Pepto-Bismol®, an over-the-counter medication for gastric
distress.
a. Based on values presented in Figure 7.7 and Tables 7.5 and 7.6, what might you expect for the
bonding atomic radius of bismuth?
b. What accounts for the general increase in atomic radius going down the group 5A elements?
c. Another major use of bismuth has been as an ingredient in low-melting metal alloys, such as those
used in fire sprinkler systems and in typesetting. The element itself is a brittle white crystalline solid.
How do these characteristics fit with the fact that bismuth is in the same periodic group with such
nonmetallic elements as nitrogen and phosphorus?
d. Bi2O3 is a basic oxide. Write a balanced chemical equation for its reaction with dilute nitric acid. If
6.77 g of Bi2O3 is dissolved in dilute acidic solution to make 0.500 L of solution, what is the
molarity of the solution of Bi3+ ion?
e.
209
Bi is the heaviest stable isotope of any element. How many protons and neutrons are present in
this nucleus?
f. The density of Bi at 25 °C is 9.808 g/cm3. How many Bi atoms are present in a cube of the element
that is 5.00 cm on each edge? How many moles of the element are present?
37. Write equations that show the processes that describe the first, second, and third ionization energies of an
aluminum atom. Which process would require the least amount of energy?
38. (a) Why does Li have a larger first ionization energy than Na? (b) The difference between the third and
fourth ionization energies of scandium is much larger than that of titanium. Why? (c) Why does Li have a
much larger second ionization energy than Be?
39. (a) What is the general relationship between the size of an atom and its first ionization energy? (b) Which
element in the periodic table has the largest ionization energy? Which has the smallest?
40. Based on their positions in the periodic table, predict which atom of the following pairs will have the
smaller first ionization energy: (a) Cl, Ar; (b) Be, Ca; (c) K, Co; (d) S, Ge; (e) Sn, Te.
41. Write the electron configurations for the following ions, and determine which have noble-gas
configurations: (a) Co2 + , (b) Sn2 + , (c) Zr4 + , (d) Ag+, (e) S2 - .
42. Find three examples of ions in the periodic table that have an electron configuration of nd8 n = 3, 4, 5,…
43. The first ionization energy and electron affinity of Ar are both positive values. (a) What is the significance
of the positive value in each case? (b) What are the units of electron affinity?
44. Although the electron affinity of bromine is a negative quantity, it is positive for Kr. Use the electron
configurations of the two elements to explain the difference.
45. Consider the first ionization energy of neon and the electron affinity of fluorine. (a) Write equations,
including electron configurations, for each process. (b) These two quantities have opposite signs. Which
will be positive, and which will be negative? (c) Would you expect the magnitudes of these two quantities to
be equal? If not, which one would you expect to be larger?
46. (a) Does metallic character increase, decrease, or remain unchanged as one goes from left to right across a
row of the periodic table? (b) Does metallic character increase, decrease, or remain unchanged as one goes
down a column of the periodic table? (c) Are the periodic trends in (a) and (b) the same as or different from
those for first ionization energy?
47. You read the following statement about two elements X and Y: One of the elements is a good conductor of
electricity, and the other is a semiconductor. Experiments show that the first ionization energy of X is twice
as great as that of Y. Which element has the greater metallic character?
48. Discussing this chapter, a classmate says, “An element that commonly forms a cation is a metal.” Do you
agree or disagree? Explain your answer.
49. Predict whether each of the following oxides is ionic or molecular: SnO2, Al2O3, CO2, Li2O, Fe2O3, H2O.
50. (a) What is meant by the terms acidic oxide and basic oxide? (b) How can we predict whether an oxide will
be acidic or basic based on its composition?
51. Chlorine reacts with oxygen to form Cl2O7. (a) What is the name of this product (see Table 2.6)? (b) Write a
balanced equation for the formation of Cl2O7(l) from the elements. (c) Under usual conditions, Cl2O7 is a
colorless liquid with a boiling point of 81 °C. Is this boiling point expected or surprising? (d) Would you
expect Cl2O7 to be more reactive toward H+(aq) or OH-(aq)? (e) If the oxygen in Cl2O7 is considered to
have the -2 oxidation state, what is the oxidation state of the Cl? What is the electron configuration of Cl in
this oxidation state?
52. Write balanced equations for the following reactions: (a) barium oxide with water, (b) iron(II) oxide with
perchloric acid, (c) sulfur trioxide with water, (d) carbon dioxide with aqueous sodium hydroxide.
53. (a) Why is calcium generally more reactive than magnesium? (b) Why is calcium generally less reactive
than potassium?
54. Write a balanced equation for the reaction that occurs in each of the following cases: (a) Potassium metal is
exposed to an atmosphere of chlorine gas. (b) Strontium oxide is added to water. (c) A fresh surface of
lithium metal is exposed to oxygen gas. (d) Sodium metal reacts with molten sulfur.
55. Potassium and hydrogen react to form the ionic compound potassium hydride. (a) Write a balanced equation
for this reaction. (b) Use data in Figures 7.10 and 7.12 to determine the energy change in kJ/mol for the
following two reactions:
K(g) + H(g)  K+(g) + H-(g) K(g) + H(g)  K-(g) + H+(g)
(c) Based on your calculated energy changes in (b), which of these reactions is energetically more favorable
(or less unfavorable)? (d) Is your answer to (c) consistent with the description of potassium hydride as
containing hydride ions?
56. Compare the elements bromine and chlorine with respect to the following properties: (a) electron
configuration, (b) most common ionic charge, (c) first ionization energy, (d) reactivity toward water, (e)
electron affinity, (f) atomic radius. Account for the differences between the two elements.
57. Until the early 1960s the group 8A elements were called the inert gases. (a) Why was the term inert gases
dropped? (b) What discovery triggered this change in name? (c) What name is applied to the group now?
58. Write a balanced equation for the reaction that occurs in each of the following cases: (a) Ozone decomposes
to dioxygen. (b) Xenon reacts with fluorine. (Write three different equations.) (c) Sulfur reacts with
hydrogen gas. (d) Fluorine reacts with water.