Question

Which of the following are the merits of the Mendeleev's periodic table?

• A. Vacant slots were kept for elements not discovered back then.
• B. Elements with similar properties were kept in the same group.
• C. The position of hydrogen was finally fixed.
• D. Corrections in the atomic masses of certain elements were made.

Answer 1

Answer: (A), (B), (D)

The correct options are
A Vacant slots were kept for elements not discovered back then.
B Elements with similar properties were kept in the same group.
D Corrections in the atomic masses of certain elements were made.

The merits of the Mendeleev's periodic table are:

• Elements with similar properties were kept in the same group.
• Corrections in the atomic masses of certain elements were made as they could not be placed in the correct group which had similar properties.
• Spaces left for certain elements which were not known at that time with their predicted properties were later occupied by germanium and gallium.

Mendeleev could not assign a correct position to hydrogen in his periodic table due to the similarity in its properties with halogens as well as alkali metals. This was one of the demerits of Mendeleev's periodic table.