Question

what are the similarities in properties of elements in Halogen group?

Answer 1

All in this group are characterized by the presence of 7 e- in an outer shell, and hence have the ability to gain an e- to form negative ions w/ a completed octet of valence e-’s.

All these elements share traits of being very reactive and in particular form substitution compounds w/ numerous organic compounds.

Although these elements also have other valences all have a -1 valence in common.