Question

atchivememt and drobags of mandeleve periodic table​

Answer 1

answer are given above

Answer 2

Merits r as follows

1. There was a regular gradation in physical nd chemical properties of elements.

2. The group no.indicates highest oxidation state that can attain .

3. There was many. vacant places in Mendeleev periodic table who were yet to be discovered.

4.His arrangements helped to correct atomic masses of a number elements.

Demerits

1. If the elements were arranged according to the atomic mass show evident periodicity of properties.

2. Elements which r similar regards to their chemical properties.