Which group of elements could be placed

Group of noble gases (called zero group) could be placed in the Mendeleev’s Periodic Table with out disturbing the original order.

Reasons : Elements present in a group have same valency in the Mendeleev’s Periodic Table. Based on their electronic configuration, the

members of noble gas family have zero valency. That is why they are called inert gases. They could be easily placed in the Mendeleev’s Periodic

Table as a separate group without disturbing the arrangement of other elements.