3.2.2 Group 2

Question 1

As you go down group 2 what happens to atomic radius?why?

Answer 1

increases, as number of protons increases the amount of shielding increases so more inner energy levels so weaker electrostatic forces of attraction between the nucleus and outer shell of electrons.

Question 2

What happens to first ionisation energies down group 2? Why?

Answer 2

Decrease, atomic radius increases meaning there are weaker forces of attraction between the nucleus and the outermost electron making it easier to remove the outermost electron.

Question 3

What happens to melting points down group 2? Why?

Answer 3

Decreases, increased number of energy levels decrease the electrostatic attraction between delocalized electrons and the metal ions.

Question 4

What happens to the solubility of group 2 metal hydroxide?

Answer 4

increases

Question 5

What happens to solubility of group 2 metal sulfates?

Answer 5

decreases

Question 6

What is the trend in reactivity with the water down group 2?

Answer 6

Reactivity increases

Question 7

What Is the use of group 2 elements and compounds?

Answer 7

• Mg(OH)2 and Ca(OH)2 used to neutralise acidic soils in agriculture. Useful as they are alkaline.
• CaO send CaCO3 used in flue gas desulphurisation. Alkaline so can react with acidic SO2.
• Mg used to displace Ti from TiCl4 as it is more reactive.
• BaSO4 used in a barium meal as insoluble and can outline gut in X-Rays.
• Acidified BaCl2 tests for sulphate ions forms insoluble baSO4 precipitate.
• Mg(OH)2 is milk of magnesia used in indigestion remedies to neutralise excess stomach acid.

Question 8

Why does magnesium have a lower boiling point than expected?

Answer 8

Magnesium has a lower melting point than expected because it has a different crystal structure compared to other metals in its group. This structure leads to weaker metallic bonds compared to other structures resulting in a lower melting point. Covalent bonding is not involved in magnesium’s crystal structure.