Question

What are the limitations of Mendeleev's periodic table? How could the modern periodic table overcome the limitations of the Mendeleev table?

Answer 1

Hint: We know that, Mendeleev arranged the elements in the increasing order of atomic mass while arranging the elements he noticed that the chemical properties of the elements and their compound showed a periodic trend.

Complete step by step answer: First, we see Mendeleev periodic law: The physical and chemical properties of the elements are the periodic function of their atomic weight. Let us see the limitations of Mendeleev’s periodic table.
Limitations of the Mendeleev table are listed below.
-Elements with large differences in properties were included within the same group. For instance, hard metals like copper and silver were included alongside soft metals like sodium and potassium.
-No proper position might be given to the element hydrogen. Within the table, the situation of hydrogen is uncertain. It had been put with alkali metals within 1A class, but certain hydrogen properties are near to those of halogens. So, it also can be put for halogens within the band.
-The increasing order of mass wasn't strictly followed throughout. For instance in cobalt and nickel & Tellurium and Indium.
-As isotopes are atoms of an equivalent element having different atomic masses, they ought to be given different positions while arranging them within the order of mass. But this wasn't done.
Now we can discuss about the modern periodic law:
-The Physical and chemical properties of the elements are periodic functions of their atomic numbers of an element.
-The modern table overcomes the restrictions of Mendeleev’s periodic table which are listed below,
-Moseley realized that number is the fundamental property of a component rather than its weight.
He arranged the weather within the table consistent with their atomic numbers.
This arrangement removes the matter of atomic weights.
Within the modern table, isotopes are put alongside their elements.

Note: We must remember that the Mendeleev's periodic table is widely accepted mainly because he identified the characteristics and placement of elements that have to be discovered and he left spaces in the table to place the elements. He could also predict the properties of the undiscovered elements.