On the periodic table, which group of elements is not possible to form an ionic bond with?

Answer: 18 group.

The group 18 elements of periodic table never forms a ionic bond. Only this group is the exception where all the elements present in the group does not form any ionic bond. There are other elements also that do not form ionic bonds but not complete group. The noble atoms have complete outer shell so they can neither lose or gain any electron which form the group 18.

The Noble Gases because all of their shells are full; thus, they have no charge. If they have no charge, then we cannot form ionic bonds with them.