The thing that they have in common is that they are all non metals
The reason does FeCl3 serve in the electrophilic sweet-smelling substitution response amongst chlorine and benzene is that it fills in as a Lewis corrosive impetus by responding with the Cl2 and along these lines actuates it toward assault by benzene's π electrons.
You want me to explain it as well?
Their identified by the number of protons they have in the nucleus which = their electrons.
