Chapter 8

Question 1

What ions do group 2 elements form?

Answer 1

2+ ions

They are reducing agents

Question 2

Group 2 redox reactions with oxygen

Answer 2

2Mg(s)+O2(g)—>2MGO

Forms a metal oxide

Question 3

Group 2 redox reactions with water

Answer 3

Sr(s)+2H2O(l)—>Sr(OH)2(aq) +H2(g)

React with water to form an alkaline hydroxide

Question 4

Group 2 redox reaction with dilute acids

Answer 4

Forms salt and hydrogen

Mg(s)+2HCL(aq)—>MgCl2(aq)+H2(g)

Question 5

Trend in ionisation energy

Answer 5

Decreases

Question 6

Reactivity for group 2 metals

Answer 6

Increases as you go down the group

Question 7

Group 2 oxides with water

Answer 7

Forms alkaline solutions of the metal hyoxide

CaO(s)+H2O(l)—>Ca(OH)2(s)

Question 8

Solubility of hydroxides

Answer 8

Solubility of the hydroxides increases down the group so the resulting solutions contain more OH-ions and are more alkaline

Question 9

Uses of group 2 compounds

Answer 9

Calcium Hydroxide is added to the fields as lime to increase the pH of acidic soils.
Ca(OH)2(s) + 2H+(aq) —>Ca2+(aq)+2H2O(l)

Question 10

Group 2 compounds in medicine

Answer 10

Used as antacids for treating acid indigestion

Milk of magnesia is a suspension of magnesium hydroxide.

Question 11

Boiling point trend for halogens

Answer 11

More electrons
Stronger london forces
More energy required to break the intermolecular forces
Boiling point increasesv. Bbbbbcg