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- (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?
Problem 55
- 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?
Problem 56
- Discussing this chapter, a classmate says, “An element that commonly forms a cation is a metal.” Do you agree or disagree?
Problem 57
Problem 58
Discussing this chapter, a classmate says, 'Since elements that form cations are metals and elements that form anions are nonmetals, elements that do not form ions are metalloids.' Do you agree or disagree?
Problem 59
Predict whether each of the following oxides is ionic or molecular: SnO2, Al2O3, CO2, Li2O, Fe2O3, H2O.
Problem 61
Would you expect zirconium(II) oxide, ZrO, to react more readily with HCl(aq) or NaOH(aq)?
Problem 62
Arrange the following oxides in order of increasing acidity: K2O, BaO, ZnO, H2O, CO2, SO2.
Problem 63a
Chlorine reacts with oxygen to form Cl2O7. (a) What is the name of this product (see Table 2.6)?
Problem 63b
Chlorine reacts with oxygen to form Cl2O7. (b) Write a balanced equation for the formation of Cl2O71l2 from the elements.
Problem 63c
Chlorine reacts with oxygen to form Cl2O7. (c) Would you expect Cl2O7 to be more reactive toward H+1aq2 or OH-1aq2?
Problem 63d
Chlorine reacts with oxygen to form Cl2O7 . (d) 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?
Problem 64a
An element X reacts with oxygen to form XO2 and with chlorine to form XCl4. XO2 is a white solid that melts at high temperatures (above 1000 °C). Under usual conditions, XCl4 is a colorless liquid with a boiling point of 58 °C. (a) XCl4 reacts with water to form XO2 and another product. What is the likely identity of the other product?
Problem 64b
An element X reacts with oxygen to form XO2 and with chlorine to form XCl4. XO2 is a white solid that melts at high temperatures (above 1000 °C). Under usual conditions, XCl4 is a colorless liquid with a boiling point of 58 °C. (b) Do you think that element X is a metal, nonmetal, or metalloid?
Problem 64c
An element X reacts with oxygen to form XO2 and with chlorine to form XCl4. XO2 is a white solid that melts at high temperatures (above 1000 °C). Under usual conditions, XCl4 is a colorless liquid with a boiling point of 58 °C. (c) By using a sourcebook such as the CRC Handbook of Chemistry and Physics, try to determine the identity of element X.
Problem 65a,b,d
Write balanced equations for the following reactions: (a) boron trichloride with water (b) cobalt (II) oxide with nitric acid (d) carbon dioxide with aqueous barium hydroxide.
Problem 66
Write balanced equations for the following reactions: (a) sulfur dioxide with water (b) lithium oxide in water (c) zinc oxide with dilute hydrochloric acid (d) arsenic trioxide with aqueous potassium hydroxide.
- (a) Why is calcium generally more reactive than beryllium? (b) Why is calcium generally less reactive than rubidium?
Problem 67
- Copper and calcium both form +2 ions, but copper is far less reactive. Suggest an explanation, taking into account the ground-state electron configurations of these elements and their atomic radii.
Problem 68
Problem 69a
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.
Problem 69a,b,c
Write a balanced equation for the reaction that occurs in each of the following cases: (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.
Problem 70a
Write a balanced equation for the reaction that occurs in each of the following cases: (a) Cesium is added to water.
Problem 70c
Write a balanced equation for the reaction that occurs in each of the following cases: (c) Sodium reacts with oxygen.
Problem 71
(a) As described in Section 7.7, the alkali metals react with hydrogen to form hydrides and react with halogens to form halides. Compare the roles of hydrogen and halogens in these reactions. Write balanced equations for the reaction of fluorine with calcium and for the reaction of hydrogen with calcium. (b) What is the oxidation number and electron configuration of calcium in each product?
- Potassium and hydrogen react to form the ionic compound potassium hydride. (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?
Problem 72
Problem 72b
Potassium and hydrogen react to form the ionic compound potassium hydride. (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)
- 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
Problem 73
Problem 74a
Little is known about the properties of astatine, At, because of its rarity and high radioactivity. Nevertheless, it is possible for us to make many predictions about its properties. (a) Do you expect the element to be a gas, liquid, or solid at room temperature?
Problem 74b
Little is known about the properties of astatine, At, because of its rarity and high radioactivity. Nevertheless, it is possible for us to make many predictions about its properties. (b) Would you expect At to be a metal, nonmetal, or metalloid? Explain.
Problem 74c
Little is known about the properties of astatine, At, because of its rarity and high radioactivity. Nevertheless, it is possible for us to make many predictions about its properties. (c) What is the chemical formula of the compound it forms with Na?
- (a) Why was the term inert gases dropped? (b) What discovery triggered this change in name? (c) What name is applied to the group 18 elements now?
Problem 75