Chaper 9

Question 1

State the general electronic configuration of Group 2 elements.

Answer 1

ns².

Question 2

Describe the trend in atomic radius down Group 2.

Answer 2

Atomic radius increases due to added electron shells.

Question 3

Explain the trend in first ionisation energy down Group 2.

Answer 3

Decreases due to increasing atomic radius and shielding.

Question 4

What is the trend in reactivity down Group 2?

Answer 4

Reactivity increases as ionisation energy decreases.

Question 5

Describe the reaction of magnesium with water.

Answer 5

Mg + 2H₂O → Mg(OH)₂ + H₂ (slow with cold water, faster with steam).

Question 6

Explain the trend in melting points down Group 2.

Answer 6

Melting points generally decrease due to weaker metallic bonding from larger ions.

Question 7

Describe the trend in solubility of Group 2 hydroxides.

Answer 7

Solubility increases down the group.

Question 8

Describe the trend in solubility of Group 2 sulfates.

Answer 8

Solubility decreases down the group.

Question 9

What is the test for sulfate ions?

Answer 9

Add BaCl₂ solution; white precipitate of BaSO₄ forms.

Question 10

Explain the use of calcium hydroxide in agriculture.

Answer 10

Neutralises acidic soil to improve crop growth.