0 0 Moodle
Home Revision Notes Courses For Schools Blog My Account Cart
Moodle
AQA A Level Chemistry

3.2.2
Group 2

Section 3.2.2 covers the trends in atomic radius, first ionisation energy and melting point from magnesium to barium, the reactions with water, magnesium in the extraction of titanium, the solubilities of the hydroxides and sulfates, the uses of magnesium hydroxide, calcium hydroxide, calcium oxide and calcium carbonate, and the acidified barium chloride test for sulfate ions. Group 1 is kept on the pages for comparison; the thermal stability and full tests pages are revision support for required practical 4.

Exam Paper
Paper 1 & 3
7405/1 and 7405/3
Specification Points
3.2.2 i – x
10 statements
Topic Parts
6 pages
Revision notes available
Exam Board
AQA
7405 (2015 onwards)

Revision Notes

Work through 3.2.2 Group 2 in a structured sequence.

Down the group
Group
Trends
1
Available

Trends Down Groups 1 and 2

The trends down Group 2: atomic radius, ionisation energies, melting points and the increase in reactivity down the group.

Start revising
The elements
Metal
Reactions
2
Available

Reactions of the Group 1 and 2 Elements

The reactions of the Group 2 elements with oxygen, chlorine, water, steam and dilute acids, with equations, observations and redox analysis.

Start revising
Bases
Oxides and
Hydroxides
3
Available

Oxides, Hydroxides and Carbonates

Group 2 oxides, hydroxides and carbonates: reactions with water and acids, pH trend, and uses of Ca(OH)₂, Mg(OH)₂ and CaCO₃.

Start revising
Opposite trends
Solubility
Trends
4
Available

Solubility Trends and the Sulfate Test

Group 2 solubility trends: hydroxides and sulfates, Mg(OH)₂ and BaSO₄, the acidified barium chloride test for sulfate ions and barium meals.

Start revising
Heat and light
Thermal
Stability
5
Available

Thermal Stability and Flame Colours

Thermal stability of Group 1 and 2 nitrates and carbonates, polarisation by the cation, the experiments, and flame colours explained by electron transitions.

Start revising
Qualitative analysis
Tests for
Ions
6
Available

Tests for Ions

Tests for carbonate, hydrogencarbonate, sulfate, halide and ammonium ions, with ionic equations and the order of tests on an unknown.

Start revising
Specification Coverage

3.2.2 Group 2, the Alkaline Earth Metals – AQA A Level Chemistry

The following AQA specification points outline the knowledge and skills students are expected to demonstrate. Wording follows the AQA A Level Chemistry (7405) specification.

3.2.2 Group 2, the alkaline earth metals

i
The trends in atomic radius and first ionisation energy of the elements Mg–Ba, and their explanations.
ii
The trend in melting point of the elements Mg–Ba, explained in terms of their structure and bonding.
iii
The reactions of the elements Mg–Ba with water.
iv
The use of magnesium in the extraction of titanium from TiCl₄.
v
The relative solubilities of the hydroxides of the elements Mg–Ba in water; Mg(OH)₂ is sparingly soluble.
vi
The use of Mg(OH)₂ in medicine and of Ca(OH)₂ in agriculture.
vii
The use of CaO or CaCO₃ to remove SO₂ from flue gases (taught on the 3.3.2 Alkanes pages).
viii
The relative solubilities of the sulfates of the elements Mg–Ba in water; BaSO₄ is insoluble.
ix
The use of acidified BaCl₂ solution to test for sulfate ions, and the use of BaSO₄ in medicine.
x
Explain why BaCl₂ solution is used to test for sulfate ions and why it is acidified.