3.1.2
Group 2
Section 3.1.2 covers the s² outer shell of the Group 2 elements and their redox reactions with oxygen, water and dilute acids, the trend in reactivity explained by the first and second ionisation energies, the action of water on the oxides and the increasing alkalinity of the solutions, and the uses of Group 2 compounds as bases. The solubility and thermal stability pages are revision support that connects this section to 3.1.4.
Revision Notes
Work through 3.1.2 Group 2 in a structured sequence.
Trends
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 revisingReactions
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 revisingHydroxides
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 revisingTrends
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 revisingStability
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 revising3.1.2 Group 2 – OCR A Level Chemistry A
The following OCR A learning outcomes state what candidates should be able to do. Wording is taken from the OCR A Level Chemistry A (H432) specification.
3.1.2 Group 2
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