Describe two anomalies of Mendeleev’s periodic classification of element.

Question

Describe two anomalies of Mendeleev&#x2019;s periodic classification of element.

Philoid · Accepted Answer

The two anomalies were:-

1) It could not explain the position of isotopes. Since the elements were arranged according to the atomic masses, isotopes should have been given separate positions, which was not the case. The isotopes were not given separate places. This could not be explained by Mendeleev’s periodic law.

2) It could not explain the wrong order of atomic masses. When the elements were put in their correct group according to their chemical properties, it was discovered that the element with higher atomic mass came first and the element with lower atomic mass came later.