Answer:
Same within the groups...
Different within the periods...
Explanation:
The outer configuration is same with a group because of their arrangement in the periodic table. If we see group 1a of alkalies, all of them have 1 electron in their outer shell and this order goes on increasing up-to noble gases that have 8 electrons in their outer shell each.
This arrangement is called periodicity of the periodic table and elements are arranged according to the periodic law.
Along a period, these properties of outer configuration goes on increasing than within the group.
