3.1.2 Group 2

Question 1

Redox reactions in group 2

Answer 1

Each metal atom is oxidised, loses 2 electrons to form 2+ ion, reducing agent

Question 2

Group 2 redox reaction with oxygen

Answer 2

Form metal oxide with general formula MO
Reactivity increases down the group

Question 3

Group 2 redox reaction with water

Answer 3

Form alkaline hydroxide, M(OH)2, and H2
Reactivity increases down the group

Question 4

Group 2 redox reaction with dilute acids

Answer 4

Forms salt and H2
Reactivity increases down the group

Question 5

Why does reactivity increase down group 2

Answer 5

Ionisation energies decrease down the group because attraction between nucleus and outer electrons decreases due to increasing atomic radius and increasing shielding
Therefore, elements are more reactive down the the group

Question 6

Group 2 oxide reactions with water

Answer 6

Release OH-, form alkaline solutions of metal hydroxide

Question 7

Solubility of group 2 hydroxides

Answer 7

Solubility increases down group, more alkaline down the group

Question 8

Uses of group 2 compounds in agriculture and equation

Answer 8

Calcium hydroxide added to fields to increase pH of acidic soils , neutralises the acid and forms water
Ca(OH)2 (s) + 2H+ (aq) -> Ca2+ (aq) + 2H2O (l)

Question 9

Uses of group 2 compounds in medicine and equation

Answer 9

Group 2 bases used as antacids for acid indegestion
Mg(OH)2 (s) + 2HCl (aq) -> MgCl2(aq) + 2H2O (l)
CaCO3 (s) + 2HCl (aq) -> CaCl2 (aq) + H2O (l) + CO2 (g)