Answer:
Various limitations of Mendeleev's periodic table are:-
Position of hydrogen - he couldn't assign a correct position to hydrogen as it showed properties of both alkali and halogens .
Position of isotopes - he considered that the properties of elements are a function of their atomic masses. Hence isotopes of a same element couldn't be placed.
In the d-block , elements with lower atomic number were placed before higher atomic number.
Explanation:
conduction - the transfer of heat to an object through contact
Given :
Number of molecules of 
.
To Find :
How many moles are in given number of molecules.
Solution :
We know, in 1 moles of any element/compound contains 
at atoms/molecules.
So, number of moles in 
molecules are :
Therefore, number of moles are 8.97 .
