Question

what are the similarities in properties of elements of halogen family? plz answer

Answer 1

when any element of halogen group gets added to a hydrocarbon group to changes the chemical properties of it. This is a similarity of them

Answer 2

The halogens all have the property that they have 7 electrons in their outer shell.

For quantum mechanical reasons, there is ‘room’ for 8 electrons in the outer shell. So the halogens will react rather strongly with elements that have one or two electrons in their outer shell. These electrons are loosely held by their nucleus because they are far from it, relatively speaking.
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