Group 7 (halogens)

Halogens react with most metals to make salts.

They are very reactive because they have 7 electrons in their outer shell.

The reactivity of the elements decreases as you go down the group because the atoms get bigger.

Properties of group 7 elements :

• all have 7 electrons in their outer shell
• all exist as diatomic molecules E.g. F2, Cl2
• halogens react with water and metals to form salts
• they undergo displacement reactions

Appearence of halogens :

• flourine is a pale yellow gas
• chlorine is a pale green gas
• bromine is a red-brown liquid
• iodine is a black shiny solid

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