Question

what was the basis of the earliest statement made for the classification and grouping of elements

Answer 1

Heya friend!!
Rajdeep here...

The elements were classified and groups in increasing order of their ATOMIC MASSES. There was some drawbacks seen after the discovery of isotopes. So, the Mendeleev's Periodic table is not used any more.

The elements in the modern periodic table are classified on the basis of increasing ATOMIC NUMBERS.

Thanks!