Which group of elements could be placed in mendeleev's periodic table without disturbing the original order ? Give reason.

Explanation

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 valence in the Mendeleev's Periodic table. Based on their electronic configuration, the member 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.