group 2

Question 1

What is formed when group 2 elements react with

oxygen?

Answer 1

Group 2 metal oxide

This is a redox reaction

Question 2

What is observed when group 2 elements react with

oxygen?

Answer 2

● Beryllium only reacts in powdered form.
● Magnesium burns with an intense white flame.
● Calcium burns with a bright white flame (red at the
top).
● Strontium is reluctant to start burning but burns
intensely with a white flame.
● Barium burns with a white flame.

Question 3

Write an equation for the reaction between calcium

and oxygen

Answer 3

Ca(s) + ½O2(g) → CaO(s)

Question 4

How do group 2 elements react with water?

Answer 4

An alkaline hydroxide and hydrogen gas

This is a redox reaction

Question 5

Describe the trend in the reactions with water as you

go down group 2

Answer 5

As you go down the group, the reactions

become more vigorous.

Question 6

Write an equation for the reaction between strontium

and water

Answer 6

Sr + 2H2O → Sr(OH)2 + H2

Question 7

Why does beryllium only react with steam at very

high temperatures and not with cold water?

Answer 7

Because beryllium is the least reactive

group 2 metal.

Question 8

Why does magnesium stop reacting with cold water

after a short time?

Answer 8

Because an insoluble coat of magnesium

hydroxide forms on the surface.

Question 9

What is formed when group 2 elements react with

dilute acids?

Answer 9

A salt and hydrogen gas

This is a redox reaction

Question 10

Write an equation for the reaction between

magnesium and hydrochloric acid

Answer 10

Mg + 2HCl → MgCl2 + H2

Question 11

Describe the trend in the reactivity of group 2 metals

with hydrochloric acid

Answer 11

Reactivity increases / the reactions get

more vigorous.

Question 12

Describe and explain the trend in the reactivity of

group 2 metals with sulfuric acid

Answer 12

The reactions do not get more vigorous down the group due to the solubility of
the sulfates produced.

• Beryllium and magnesium: soluble sulfates so similar reaction as with HCl
• Calcium: sparingly soluble sulfate
• Strontium and barium: insoluble sulfates

Calcium, strontium and barium only react with sulfuric acid for a short time as
the formation of the insoluble sulfate on the metal stops the reaction.

Question 13

Why might a precipitate be seen when a group 2

oxide reacts with water?

Answer 13

Group 2 hydroxides are only slightly 
soluble in water so when the solution is 
saturated, the metal hydroxide doesn’t 
dissolve (meaning it appears as a 
precipitate).

Question 14

Write an equation for the reaction between calcium

oxide and water

Answer 14

CaO(s) + H2O(l) → Ca(OH)2(aq)

Question 15

Describe the trend in the solubility of group 2

hydroxides. Use this to explain the trend in pH

Answer 15

The solubility of group 2 hydroxides
increases down the group. As a result,
more OH- ions are release in solution
meaning pH increases down the group.

Question 16

Which group 2 oxide doesn’t react with water?

Answer 16

Beryllium oxide

Question 17

What is formed when group 2 oxides react with dilute

acids?

Answer 17

A salt and water

Question 18

Write an equation for the reaction between barium

oxide and hydrochloric acid

Answer 18

BaO + 2HCl → BaCl2 + H2O

Question 19

How do group 2 hydroxides behave in water? Use

Ca(OH)2 as an example

Answer 19

Group 2 hydroxides dissociate in water
to form their constituent ions:

         2+       - Ca(OH)2(s) → Ca (aq) + 2OH (aq)

Question 20

What is formed when group 2 hydroxides react with

dilute acids?

Answer 20

A salt and water

E.g. Ca(OH)2 + 2HCl → CaCl2 + 2H2O

Question 21

How do group 2 carbonates behave in water?

Answer 21

All group 2 carbonates are sparingly
soluble in water. They do not react with
water.

Question 22

What is formed when group 2 carbonates react with

dilute acids?

Answer 22

A salt, water and carbon dioxide gas

Question 23

Write an equation for the reaction between

magnesium carbonate and nitric acid

Answer 23

MgCO3 + 2HNO3 → Mg(NO3)2 + CO2 + H2O

Question 24

Describe how group 2 nitrates thermally decompose

Answer 24

Upon heating, group 2 nitrates
decompose to form a group 2 metal
oxide, nitrogen dioxide and oxygen gas.

Question 25

Write an equation for the thermal decomposition of | strontium nitrate

Answer 25

Sr(NO3)2 → SrO + 2NO2 + ½O2

Question 26

Describe the thermal decomposition of group 2 | carbonates

Answer 26

Upon heating, group 2 carbonates decompose to form a group 2 oxide and carbon dioxide. E.g. CaCO3 → CaO + CO2

Question 27

What is the use of Ca(OH)2 and CaCO3 in agriculture?

Answer 27

● Both compounds can be added to soil to raise the pH so that it is not too acidic to grow crops. This is because they react with and neutralise acids. ● CaCO3 is used in the manufacture of quicklime, slaked lime, cement and mortar. ● Ca(OH)2 is used for cement, mortar and sewage treatment.