21.2.1 The Alkali Metals

Question 1

The Alkali Metals

Answer 1

• Group 1(IA) elements other than hydrogen are called alkali metals.
• All alkali metals form cations with a 1+ charge and are very soft.
• Three important alkali metals are lithium, sodium, and potassium.

Question 2

note 1

Answer 2

• Group 1(IA) elements other than hydrogen are called alkali metals.
• Alkali metals form cations with a 1+ charge.
• In their pure metallic form, alkali metals are relatively soft. Francium is believed to be a liquid at room temperature, although a macroscopic quantity has never been isolated.
• Alkali metals react with water, producing a basic solution and hydrogen gas.
• Lithium is isolated from spodumene (LiAl(SiO 3 ) 2 ).
• Lithium metal is obtained through the electrolysis of molten lithium chloride (LiCl).
• Because of its low reduction potential, lithium is used in
  batteries.
• Lithium hydroxide is used in CO 2 scrubbers.

Question 3

note 2

Answer 3

• Sodium metal is obtained through the electrolysis of molten sodium chloride (NaCl).
• Sodium metal reacts with water and oxygen.
• Electrolysis of NaCl in aqueous solution produces hydrogen gas, chlorine gas, and sodium hydroxide (NaOH).
• NaOH has several uses, including aluminum purification, soap production, and drain cleaners.
• Sodium bicarbonate (NaHCO 3 ) is baking soda.
• Sodium carbonate (Na 2 CO 3 ) is used to make glass and as a water softener. The carbonate ion (CO 32– ) precipitates with calcium ion (Ca + ), removing it from solution. CO 32– (aq) + Ca 2+ (aq)
• Potassium metal is obtained through reduction of potassium chloride (KCl) by sodium metal.
• Potassium metal reacts with water, producing a basic solution and hydrogen gas.
• Potassium metal reacts with oxygen (O 2 ) to form potassium superoxide (KO 2 ).
• KO 2 reacts with carbon dioxide (CO 2 ) and water (H 2 O) to form potassium bicarbonate (KHCO 3 ) and oxygen (O 2 ). This reaction is used in oxygen masks.

Question 4

Which of the following is not a characteristic of alkali metals?

Answer 4

High ionization energy

Question 5

Which of the following statements concerning alkali metals is false?

Answer 5

The valence shell configuration of alkali metals is ns ^2

Question 6

Which of the following statements is false?

Answer 6

The reaction of an alkali metal with water is endothermic.

Question 7

Which of the following elements is an alkali metal?

Answer 7

Lithium, Li

Question 8

Which of the following is not a characteristic of most metals?

Answer 8

Metals have high ionization energies.

Question 9

Why is lithium hydroxide used instead of sodium hydroxide to remove carbon dioxide from the air in confined areas such as space stations?

Answer 9

Lithium hydroxide is lighter than sodium hydroxide.

Question 10

Lithium is produced from the mineral spodumene (LiAl(Si2O6 )) in several steps. One of the intermediate steps is lithium carbonate. Lithium carbonate is useful in treating what?

Answer 10

Manic-depressive disorder

Question 11

What is the most common oxidation state for alkali metals?

Answer 11

+1

Question 12

Which of the following does not apply to alkali metals?

Answer 12

Strong oxidizing agents

Question 13

Which two alkali metals are essential elements in living organisms?

Answer 13

Sodium and potassium