Question

The drawbacks of Mendeleev's Periodic Table are:

• A. Position of Hydrogen was unclear
• B. Position of Lanthanides and Actinides
• C. Position of Isotopes
• D. All the (a) ,(b) and (c)

Answer 1

The correct option is D

All the (a) ,(b) and (c)

Mendeleev's table had some major drawbacks:

(i) The position of Hydrogen - Hydrogen resembles the elements of both group 1 and group 7. So its position was controversial in the table.

(ii) The position of isotopes - On the basis of atomic masses, different isotopes of the same element should be given different positions in the periodic table. But they were assigned a single position.

(iii) The position of Lanthanides and Actinides - Lanthanides and Actinides were placed at the bottom of the periodic table. They were not placed in the regular periodic table.

So answer will be A, B, C