Question

What physical and chemical properties of elements were used by Mendeleev in creating his periodic table? List two observations which posed a challenge to Mendeleev’s Periodic Law.

Answer 1

The chemical property used was the nature of oxide and hydride formed i.e. similarity in chemical properties were used by Mendeleev. The two observations that posed challenge in Mendeleev Periodic Law were: i Arranging elements according to the increasing order of atomic mass could not be maintained.

Answer 2

Answer:

Atomic mass as a physical property and nature and formulae of oxide and hydride formed, and chemical property was used by Mendeleev.

Following are the two observations which posed a challenge to Mendeleev’s Periodic Law.

(i) Increasing order of atomic weights could not be maintained while matching chemical properties. Chemical properties do not depend upon atomic mass.

(ii) Isotopes have different atomic mass but same chemical properties.