Question 1

Which of the following best explains why lithium forms a normal oxide (Li2O) upon combustion, while potassium forms a superoxide (KO2)?

Accepted Answer

Lithium's small ionic radius and high charge density favor the formation of the smaller oxide ion, while potassium's larger size stabilizes the larger superoxide ion.

Question 2

Which property increases as you move from left to right across a period in the periodic table?

Accepted Answer

Electronegativity

Question 3

A patient is treated for bipolar disorder with lithium carbonate. Which property of lithium salts is most relevant to their use in medicine?

Accepted Answer

Lithium salts are highly soluble and strongly hydrated, allowing for controlled release in the body.

Question 4

Which equation correctly represents the reaction of sodium peroxide with carbon dioxide in an emergency breathing device?

Accepted Answer

$$2 \mathrm{Na}_2\mathrm{O}_2 (s) + 2 \mathrm{CO}_2 (g) \rightarrow 2 \mathrm{Na}_2\mathrm{CO}_3 (s) + \mathrm{O}_2 (g)$$

Question 5

Which of the following best describes the amphoteric nature of aluminum hydroxide?

Accepted Answer

It reacts with both acids and bases, forming salts with acids and complex ions with bases.

Question 6

A sample of bauxite is purified to obtain aluminum oxide. Which process is used to reduce aluminum oxide to metallic aluminum on an industrial scale?

Accepted Answer

Electrolysis of molten aluminum oxide dissolved in cryolite

Question 7

Which of the following statements about the diagonal relationship between lithium and magnesium is correct?

Accepted Answer

Both form sparingly soluble fluorides and strongly hydrated salts.

Question 8

Which of the following is a correct statement about the solubility of Group 2 hydroxides in water?

Accepted Answer

Solubility increases down the group, with barium hydroxide being the most soluble.

Question 9

Which of the following best explains why beryllium chloride (BeCl2) is a poor conductor in the molten state?

Accepted Answer

BeCl2 is a covalent compound, so it does not produce free ions in the melt.

Question 10

Which of the following reactions represents the thermal decomposition of calcium carbonate, a key step in the manufacture of cement?

Accepted Answer

$$\mathrm{CaCO}_3 (s) \rightarrow \mathrm{CaO} (s) + \mathrm{CO}_2 (g)$$

Question 11

Which of the following best describes the role of crown ethers in alkali metal chemistry?

Accepted Answer

They selectively complex specific alkali metal cations, increasing their solubility in organic solvents.

Question 12

Which of the following is a correct statement about the industrial production of sodium metal?

Accepted Answer

Sodium is produced by the electrolysis of molten sodium chloride in a Downs cell.

Question 13

Which of the following best explains why carbon can form long chains and rings, while silicon cannot?

Accepted Answer

Carbon forms stronger single bonds due to its smaller size and effective orbital overlap.

Question 14

Which of the following is a real-world application of sodium carbonate (Na2CO3)?

Accepted Answer

Used in the manufacture of glass.

Question 15

Which of the following best describes the amphoteric behavior of beryllium hydroxide?

Accepted Answer

It reacts with both acids and bases, forming Be2+ in acid and [Be(OH)4]2- in base.

Question 16

Which of the following is a correct statement about the use of lead in modern society?

Accepted Answer

Lead is used in storage batteries and as a radiation shield, but its use in plumbing and gasoline has been reduced due to toxicity.

Question 17

Which of the following equations represents the reaction of aluminum with aqueous hydroxide?

Accepted Answer

$$2 \mathrm{Al} (s) + 2 \mathrm{OH}^- (aq) + 6 \mathrm{H}_2\mathrm{O} (l) \rightarrow 2 [\mathrm{Al(OH)}_4]^- (aq) + 3 \mathrm{H}_2 (g)$$

Question 18

Which of the following best explains why tin and lead can exist in both +2 and +4 oxidation states, while carbon and silicon are typically found in the +4 state?

Accepted Answer

Tin and lead have lower ionization energies for the removal of p electrons, making the +2 state more accessible due to the inert pair effect.

Question 19

Which of the following is a correct statement about the use of silicates in industry?

Accepted Answer

Silicates are used in ceramics and glass manufacturing due to their network structures.

Chemistry of the Main-Group Elements I: Groups 1, 2, 13, and 14

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