What are the limitations of Mendeleeff’s periodic table? How could the modern periodic table overcome the limitations of Mendeleeff’s table?

Limitations of Mendleeff’s periodic table are:

i. Certain elements of highest atomic weight precede those with lower atomic weight. For example – Tellurium (atomic weight 127.6) precedes iodine (atomic weight 126.9)

ii. Elements having different properties were placed in the same group.

iii. Isotopes were discovered long time after Mendeleev put forth the periodic table. As isotopes have the same chemical properties but different atomic masses, a challenge was posed in placing them in Mendeleev’s periodic table.

The modern periodic table overcome the limitations of Mendeleeff’s table:

i. Moseley realized that atomic number is the fundamental property of an element than its weight.

ii. He arranged the elements in the periodic table according to their atomic numbers.

iii. This arrangement removes the problem of atomic weights.

iv. In the modern periodic table, isotopes are put together with their elements.