Question

Why were noble gases not a part of mendeleev's periodic table in the beginning?

Answer 1

Noble gases were not the part of mendeleev's periodic table as the noble gases were not found at that time.

Hope it helps....

Answer 2

The noble gasses were not mentioned in Mendeleev periodic table because when he made the table the noble gasses were not found but after they were found he made place for it without disturbing any elements in the table