Question

why did Mendeleev give give gap in the periodic table​

Answer 1

Explanation:

But instead of seeing this as a problem, Mendeleev thought it simply meant that the elements which belonged in the gaps had not yet been discovered. He was also able to work out the atomic mass of the missing elements, and so predict their properties. And when they were discovered, Mendeleev turned out to be right.

Answer 2

Answer:

mendeleev give gap in the P.T because he predicted that there may be some element which may be discovered later.