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Group 7

Key Stage 4

Meaning

Group 7 elements, also known as Halogens on the Periodic Table are the elements which have 7 electrons in their outer shell.

PeriodicTableGroups.png
Group 7 elements are shown in green at the right of the Periodic Table.

About the Halogens

The Halogens have similar chemical properties because they all have 7 electrons on their outer shell.
Halogens all produce ions with a -1 relative charge because they gain an electron in chemical reactions.

The Halogens in order from most reactive to least reactive are:

Chemical Properties

The reactivity of Halogens decreases as you go down the Periodic Table.
Halogens all react strongly as bleaching agents.
Halogens all produce acids when combined with Hydrogen.
Halogens are toxic to bacteria and are used in disinfectants.
Group7ElectronShells.png
Group7ElectronShielding.png
In a chemical reaction an extra electron is added to the outer shell.

The reactivity decreases as you go down the group because:

Physical Properties

The physical properties of Halogens changes significantly as you go down the Periodic Table:

The density, melting point and boiling point all increase as you go down the Periodic Table.

References

AQA

Group 7 (halogens), pages 131-4, GCSE Combined Science Trilogy 1, Hodder, AQA
Group 7 (halogens), pages 44-5, 46, GCSE Chemistry; Student Book, Collins, AQA
Group 7, page 110, GCSE Combined Science; The Revision Guide, CGP, AQA
Group 7, page 25, GCSE Chemistry; The Revision Guide, CGP, AQA
Group 7, pages 16-18, GCSE Chemistry, Hodder, AQA
Group 7, pages 28-29, 31, GCSE Chemistry; Third Edition, Oxford University Press, AQA
Group 7, pages 61-63, GCSE Chemistry, CGP, AQA
Group 7, pages 61-63, GCSE Combined Science Trilogy; Chemistry, CGP, AQA
Halogens, page 110, GCSE Combined Science; The Revision Guide, CGP, AQA
Halogens, pages 131-4, GCSE Combined Science Trilogy 1, Hodder, AQA
Halogens, pages 16-18, GCSE Chemistry, Hodder, AQA
Halogens, pages 25, 79, GCSE Chemistry; The Revision Guide, CGP, AQA
Halogens, pages 28-29, 31, 158, 188-189, GCSE Chemistry; Third Edition, Oxford University Press, AQA
Halogens, pages 44-5, 46, GCSE Chemistry; Student Book, Collins, AQA
Halogens, pages 61-63, GCSE Chemistry, CGP, AQA
Halogens, pages 61-63, GCSE Combined Science Trilogy; Chemistry, CGP, AQA
Halogens; reaction with alkenes, pages 178-9, GCSE Chemistry, Hodder, AQA

Edexcel

Group 7, pages 20, 74, 75, GCSE Chemistry; The Revision Guide, CGP, Edexcel
Group 7, pages 40, 49, 213-215, GCSE Chemistry, CGP, Edexcel
Group 7, pages 83, 124, 125, GCSE Combined Science; The Revision Guide, CGP, Edexcel
Halogens, pages 124, 125, GCSE Combined Science; The Revision Guide, CGP, Edexcel
Halogens, pages 130-131, GCSE Chemistry, Pearson, Edexcel
Halogens, pages 244-245, GCSE Combined Science, Pearson Edexcel
Halogens, pages 40, 49, 214-217, 277, 278, GCSE Chemistry, CGP, Edexcel
Halogens, pages 74, 75, GCSE Chemistry; The Revision Guide, CGP, Edexcel
Halogens; reactivity, pages 132-133, GCSE Chemistry, Pearson, Edexcel
Halogens; reactivity, pages 246-247, GCSE Combined Science, Pearson Edexcel

OCR

Group 7 (IUPAC Group 17) elements, pages 70, 71, 86, 125, 134-137, Gateway GCSE Chemistry, Oxford, OCR
Group 7, pages 122, 123, Gateway GCSE Combined Science; The Revision Guide, CGP, OCR
Group 7, pages 52, 53, Gateway GCSE Chemistry; The Revision Guide, CGP, OCR

OCR