8.1 Group 2

Question 1

What is the general reactivity trend down the group? Explain

Answer 1

It gets more reactive.

When they react they lose electrons, forming positive ions. The easier it is to lose electrons, the more reactive it is.

Ionisation energies decrease down the group showing it gets easier to lose electrons.

Question 2

Describe the trend in ionisation energy down the group. Why?

Answer 2

It decreases because :

Atomic radius increases
Shielding increases

Question 3

Describe group 2 reactions with oxygen

Answer 3

Burns in oxygen and produces a metal oxide

2Mg + O2 -> 2MgO

Question 4

Describe a metal oxides reaction with water

Answer 4

Produces a hydroxide

CaO + H2O -> Ca(OH)

Question 5

Describe the solubility of hydroxides down the group

Answer 5

It increases
pH increases
Alkalinity increases

Question 6

What are the uses of group 2 compounds as bases?

Answer 6

Neutralise soil

Antacids

Question 7

Describe the reaction of group 2 with water

Answer 7

Produces hydroxides and hydrogen

M + 2H2O -> M(OH)2 + H2

Or

Ca + 2H2O -> Ca(OH)2 + H2

Question 8

Describe the reaction of group 2 with dilute acid

Answer 8

Produces salt and hydrogen

M + 2HCl -> MCl + H2

Or

Ca + 2HCl -> CaCl2 + H2

Question 9

Are group 2 elements reducing o oxidising elements? Explain

Answer 9

Metal atom are oxidised, losing two electrons to form a 2+ ion. Another species will gain these two electrons and be reduced.

Therefore, it is a reducing agent.