Question

what physical and chemical property
of ements were used by
Mandeleer in creating
his periodic table?​

Answer 1

Answer:

The element were arranged on the basis of increasing atomic masses.

Physical Properties:

The atomic masses further influenced physical properties like melting point, density, boiling point, etc.

Chemical Properties:

Reaction with oxygen and chlorine.

Two observations which posed a challenge to Mendeleev's Periodic Law:

Position of the isotopes: The isotopes of the elements have different atomic masses. So, isotopes must occupy different positions in the periodic table.

Anomalous positions of some elements: In the periodic table put forward by Mendeleev, some elements with the higher atomic masses were placed before elements with lower atomic masses; say for example, Ar (atomic mass = 39.9) is placed before Potassium (K) (atmoic mass = 39.1)