Edexcel A Level Chemistry

Groups 1 and 2

The s-block metals are the clearest example of trends down a group. These pages explain the trends in atomic radius, ionisation energy and reactivity, the reactions of the elements and their oxides, hydroxides and carbonates, the solubility and thermal stability patterns, flame colours and the tests for ions. Edexcel Topic 4A examines Group 2 only. The Group 1 metals are kept in the tables because comparing the two groups is the quickest way to see the patterns, but questions will be set on magnesium to barium.

Exam Papers

Paper 1

9CH0/01

Specification Points

4.1 – 4.15

9 points covered

Sub-topics

5 lessons

Revision notes available

Exam Board

Edexcel

Pearson 9CH0

Revision Notes

Work through each part of Edexcel Topic 4 in a structured sequence.

Down the group

Group Trends

radius, ionisation energy, reactivity

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.

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The elements

Metal Reactions

oxygen, chlorine, water, acids

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.

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Bases

Oxides and Hydroxides

water, acids, pH, uses

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.

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Opposite trends

Solubility Trends

hydroxides up, sulfates down

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.

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Heat and light

Thermal Stability

polarisation and flame colours

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.

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Summary map

Download, print and revise the key facts of this topic at a glance.

Summary map · PDF

Groups 1 and 2 Map

Edexcel A Level Chemistry · Topic 4 Inorganic Chemistry and the Periodic Table · Groups 1 and 2

The whole section on one A4 page: trends down the groups, reactions of the metals, oxides and hydroxides, thermal stability, flame colours, and tests for ions.

Download the map6 key ideas + a data table · A4 portrait · print ready

Specification Coverage

Groups 1 and 2 – Edexcel A Level Chemistry

The following specification points outline the knowledge and skills students are expected to demonstrate for Topic 4.

4A: The elements of Groups 1 and 2

4.1

understand reasons for the trend in ionisation energy down Group 2

4.2

understand reasons for the trend in reactivity of the Group 2 elements down the group

4.3

know the reactions of the elements Mg to Ba in Group 2 with oxygen, chlorine and water

4.4

know the reactions of the oxides of Group 2 elements with water and dilute acid, and their hydroxides with dilute acid

4.5

know the trends in solubility of the hydroxides and sulfates of Group 2 elements

4.6

understand reasons for the trends in thermal stability of the nitrates and the carbonates of the elements in Groups 1 and 2 in terms of the size and charge of the cations involved

4.7

understand the formation of characteristic flame colours by Group 1 and 2 compounds in terms of electron transitions. Students will be expected to know the flame colours for Groups 1 and 2 compounds.

4.8

understand experimental procedures to show:

patterns in thermal decomposition of Group 1 and 2 nitrates and carbonates

flame colours in compounds of Group 1 and 2 elements

4C: Analysis of inorganic compounds

4.15

know reactions, including ionic equations where appropriate, for identifying:

carbonate ions, CO₃^2-, and hydrogencarbonate ions, HCO₃^–, using an aqueous acid to form carbon dioxide

sulfate ions, SO₄^2-, using acidified barium chloride solution

iii

ammonium ions, NH₄⁺, using sodium hydroxide solution and warming to form ammonia

Specification Coverage

Groups 1 and 2 – Edexcel A Level Chemistry

The following specification points outline the knowledge and skills students are expected to demonstrate for Topic 4.

4A: The elements of Groups 1 and 2

4.1

understand reasons for the trend in ionisation energy down Group 2

4.2

understand reasons for the trend in reactivity of the Group 2 elements down the group

4.3

know the reactions of the elements Mg to Ba in Group 2 with oxygen, chlorine and water

4.4

know the reactions of the oxides of Group 2 elements with water and dilute acid, and their hydroxides with dilute acid

4.5

know the trends in solubility of the hydroxides and sulfates of Group 2 elements

4.6

understand reasons for the trends in thermal stability of the nitrates and the carbonates of the elements in Groups 1 and 2 in terms of the size and charge of the cations involved

4.7

understand the formation of characteristic flame colours by Group 1 and 2 compounds in terms of electron transitions. Students will be expected to know the flame colours for Groups 1 and 2 compounds.

4.8

understand experimental procedures to show:

patterns in thermal decomposition of Group 1 and 2 nitrates and carbonates

flame colours in compounds of Group 1 and 2 elements

4C: Analysis of inorganic compounds

4.15

know reactions, including ionic equations where appropriate, for identifying:

carbonate ions, CO₃^2-, and hydrogencarbonate ions, HCO₃^–, using an aqueous acid to form carbon dioxide

sulfate ions, SO₄^2-, using acidified barium chloride solution

iii

ammonium ions, NH₄⁺, using sodium hydroxide solution and warming to form ammonia

Groups 1 and 2

Revision Notes

Summary map

Groups 1 and 2 – Edexcel A Level Chemistry

4A: The elements of Groups 1 and 2

4C: Analysis of inorganic compounds

Groups 1 and 2 – Edexcel A Level Chemistry

4A: The elements of Groups 1 and 2

4C: Analysis of inorganic compounds

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