Question

Define modern periodic law why wa sit necessary to change the basis for classification from the atomic mass to atomic number

Answer 1

modern perodic law- The physical and chemical properties of elements are periodic function of their atomic numbers.
it was neccesary for classifying elements on basis of at .no rather than at.mass because as there were anamalous pair i.e element with higher at.mass preceeds the elements with lower mass.
.

Answer 2

Explanation:

5AM the two passengers are in a car and the driver has to go