Inorganic 1 Section 2 - Unit 9: Group II metals

Question 1

State and explain the trend in atomic radius down Group 2 from Mg to Ba (2 marks)

Answer 1

• Increases

- Due to an increase in shells

Question 2

Give the formula of the hydroxide of the element in Group 2 that is most soluble in water.

Answer 2

• Ba(OH)2

Question 3

State the trend in reactivity with water of the elements down Group 2 (1 mark)

Answer 3

• Gets more reactive

Question 4

State the ionic equation, with state symbols, to show the reaction of calcium with an excess of water (1 mark)

Answer 4

Ca(s)+ 2H2O(l) ➡ Ca2+(aq) + 2OH–(aq) + H2(g)

Question 5

State and explain the trend in the first ionisation energies of the elements in Group 2 (3 marks)

Answer 5

• Decreases
• Ions get bigger
• Sp weaker attraction of ion to lost electron

Question 6

Explain why drinking magnesium sulfate solution is effective in the treatment of barium poisoning (1 mark)

Answer 6

• Insoluble barium sulfate is produced

Question 7

State and explain the trend in melting points of the elements in Group 2 (3 marks)

Answer 7

• Decreases
• Metallic bonding weakens
• Atomic size increases

Question 8

Explain how magnesium can be used to extract titanium (6)

Answer 8

• TiO2 (solid) is converted to TiCl4 (liquid)
• At 900°C
• The TiCl4 is purified by fractional distillation
• In an argon atmosphere
• The Ti is extracted by Mg
• In an argon atmosphere at 500°C

Question 9

State the ionic equation for the formation of Magnesium Hydroxide with state symbols (1 mark)

Answer 9

Mg2+(aq) + 2OH-(aq) ➡ Mg(OH)2

Question 10

State and explain the trend in the first ionisation energies of the elements in Group 2 from magnesium to barium (3 marks)

Answer 10

• Decreases
• More shells
• Weaker attraction of ion to lost electron

Question 11

State a medical use of barium sulfate and explain why this use of barium sulfate is safe (2 marks)

Answer 11

• Used in a barium meal/to absorb X-Rays

- Because it’s insoluble

Question 12

State the equation for the reaction of magnesium hydroxide with hydrochloric acid (1 mark)

Answer 12

• Mg(OH)2 + 2HCl MgCl2 + 2H2O

Question 13

Describe briefly how you would carry out the test for bromide ions with silver nitrate, acidified with dilute nitric acid, and another reagent - state what you would observe (3 marks)

Answer 13

• Add silver nitrate, then dilute ammonia
• Cream precipitate
• Precipitate dissolves slightly in dilute ammonia