Group 2- Alkaline Earth Metals

Question 1

Trend of Atomic Radius down Group 2

Answer 1

Atomic radius increases, more electron shells are added as you go down the group

Question 2

Trend of Ionisation Energy down Group 2

Answer 2

Ionisation energy decreases, more electron shells are added, shielding the outer electrons, making it easier to remove

Question 3

Trend of Reactivity down Group 2

Answer 3

Reactivity decreases, it is easier to lose electrons

Question 4

Trend of Melting Points down Group 2

Answer 4

MP generally decreases down group 2
Metallic structures with positive ions in a crystal lattice surrounded by delocalised electrons
The larger the ionic radius, the further away the delocalised electrons, and the less attraction and less energy are needed to break the bonds
Mg has the lowest MP

Question 5

Use of Magnesium in extraction of titanium from TiCl4

Answer 5

TiCl4(l) + 2Mg(s) —-> 2MgCl2 (s) + Ti (s)

Question 6

Solubility of Group 2 Hydroxides

Answer 6

Increases down the group
Mg(OH)2 is hardly soluble- White precipitate

Question 7

Solubility of Group 2 Sulfates

Answer 7

Decreases down the group
BaSO4 is insoluble

Question 8

Use of Mg(OH)2

Answer 8

Cures heartburn, base so neutralises stomach pH
Low solubility so does not damage the body

Question 9

Use of Ca(OH)2

Answer 9

Neutralises soil

Question 10

Use of BaSO4

Answer 10

Used in X-rays, dense enough to absorb and are insoluble so are safe to eat

Question 11

CaO and CaCO3 to remove SO2 from flue gases

Answer 11

CaO (s) + SO2 (g) + 2H2O (l) —-> CaSO3 (s) + 2H2O (l)
CaCO3 (s) + SO2 (g) + 2H2O (l) —-> CaSO3 (s) + 2H2O (l) + CO2 (g)

Question 12

BaCl2 to test for Sulfate Ions

Answer 12

Acidify to remove any carbonates
BaCl2 (aq) + Na2SO4 (aq) —-> 2NaCl (aq) + BaSO4 (s) (white precipitate)