9 - Group 2 Alkaline Earth metals

Question 1

Explain the trend in ionisation energies of Group 2 metals. (5)

Answer 1

• Number of electron shells increases
• Atomic radius and electron shielding increase
• Less electrostatic attraction
• Easier to remove electrons
• Less energy required

Question 2

Describe and explain the trend in atomic radius of Group 2 metals.

Answer 2

• Number of electron shells increase down group
• Atomic radius increases

Question 3

Describe and explain the trend in melting point down Group 2 metals.

Answer 3

• Atomic size increases
• Metallic bonding decreases
• Distance between nuclei and delocalised electrons increases
• Electrostatic attraction decreases
• Melting point decreases

Question 4

Describe the trend in reactivity down Group 2.

Answer 4

Increases

Question 5

What is formed when Group 2 metals react with liquid water?

Answer 5

Metal hydroxide

Question 6

Describe and give the reaction of Mg with steam.

Answer 6

Forms MgO (s), H2 (g)
White flame

Question 7

What observations happen more down Group 2 in the reaction of Group 2 metals with water?

Answer 7

Fizzing
Metal dissolving
Solution heats up

Question 8

Describe the trend in formation of a white ppt down Group 2 when reacting with water.

Answer 8

Less white ppt forms down group (form hydroxides)

Question 9

Describe the process of the extraction of Ti.

Answer 9

TiO2 + 2Cl2 + 2C –> TiCl4 + 2CO
TiCl4 + 2Mg –> Ti + 2MgCl2

Question 10

Describe the trend in solubility of Group 2 hydroxides down the group.

Answer 10

Increases

Question 11

Describe and explain the medical use of Mg(OH)2.

Answer 11

• Neutralise stomach acid
• As it is insoluble in water

Question 12

Describe and explain the agricultural use of Ca(OH)2.

Answer 12

• Neutralise acidic soil
• Partially soluble

Question 13

Describe the solubility of Group 2 sulfates down the group.

Answer 13

Decreases

Question 14

Give the solubility of barium sulfate in water.

Answer 14

Insoluble

Question 15

Describe and explain the medical use of BaSO4.

Answer 15

• Given to make X-rays of patients’ intestines.
• Insoluble so is not absorbed into blood

Question 16

Describe the test for sulfate ions.

Answer 16

Add dilute HCl
Add BaCl2
White precipitate forms of barium sulphate

Question 17

Why is HCl added to BaCl2 to test for sulfates?

Answer 17

Reacts with carbonates that would otherwise give false white Barium Carbonate precipitates.