Question

what are the similarities in properties of elements in halogen family

Answer 1

Last electronic configuration in subshell

Answer 2

all of them have electronic configuration ns^2 np^5
hence all of them accepts 1 electron to attain Nobel gas configuration of ns^2 np^6

all of them are the smallest in size in their respective periods...

the are the most electro negative elements...

all of them are non metal

hope it helps you....

:)