Group 7 Halogens
Group 7 is the p-block mirror of Group 2: the same reasoning about size and shielding, but now the halogens gain electrons instead of losing them. These pages cover the physical trends, the halogens as oxidising agents, the disproportionation reactions of chlorine and the halide ions as reducing agents together with their tests.
Revision Notes
4 revision notes, in the order the specification teaches them.
Trends in the Halogens
The trends in Group 7: states, colours, boiling points, electronegativity, reactivity and predictions for fluorine and astatine.
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Halogens as Oxidising Agents
The halogens as oxidising agents: displacement reactions, colours in water and cyclohexane, reactions with metals and hydrogen, and the reactivity trend.
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Disproportionation Reactions of Chlorine
The disproportionation of chlorine with water and with cold and hot alkali, bleach, water treatment and analogous halogen reactions.
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Halide Ions: Reducing Agents and Tests
Halide ions: reducing power with concentrated sulfuric acid, the acidified silver nitrate test and ammonia, and the hydrogen halides with ammonia and water.
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Halogens Map
Edexcel A Level Chemistry · Topic 4 Inorganic Chemistry and the Periodic Table · Group 7
The whole section on one A4 page: physical trends, displacement, halogens with metals, chlorine disproportionating, halides with H₂SO₄, and halide tests and predictions.
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Specification
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Self-assessment · 21 points
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4
- B.11 a
understand the trend in reactivity of Group 7 elements in terms of redox reactions of Cl2 with halide ions in aqueous solution followed by organic solvent
Revise - B.11 b
understand the trend in reactivity of Group 7 elements in terms of redox reactions of Br2 with halide ions in aqueous solution followed by organic solvent
Revise - B.11 c
understand the trend in reactivity of Group 7 elements in terms of redox reactions of I2 with halide ions in aqueous solution followed by organic solvent
Revise - B.12i
understand, in terms of changes in oxidation number, the following reactions of the halogens: oxidation reactions with Group 1 and 2 metals
Revise - B.12ii
understand, in terms of changes in oxidation number, the following reactions of the halogens: the disproportionation reaction of chlorine with water and the use of chlorine in water treatment
Revise - B.12iii
understand, in terms of changes in oxidation number, the following reactions of the halogens: the disproportionation reaction of chlorine with cold, dilute aqueous sodium hydroxide to form bleach
Revise - B.12iv
understand, in terms of changes in oxidation number, the following reactions of the halogens: the disproportionation reaction of chlorine with hot alkali
Revise - B.12v
understand, in terms of changes in oxidation number, the following reactions of the halogens: reactions analogous to those specified above
Revise - B.13i
understand the following reactions: solid Group 1 halides with concentrated sulfuric acid, to illustrate the trend in reducing ability of the hydrogen halides
Revise - B.13ii a
understand precipitation reactions of Cl- with aqueous silver nitrate solution followed by aqueous ammonia
Revise - B.13ii b
understand precipitation reactions of Br- with aqueous silver nitrate solution followed by aqueous ammonia
Revise - B.13ii c
understand precipitation reactions of I- with aqueous silver nitrate solution followed by aqueous ammonia
Revise - B.14 a
be able to make predictions about fluorine and its compounds using trends in halogen chemistry
Revise - B.14 b
be able to make predictions about astatine and its compounds using trends in halogen chemistry
Revise
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