Question

give three achievements and two limitations of Mendeleev's periodic table​

Answer 1

$hello$

⏩ No fixed position was given to hydrogen in the Periodic Table. ⏩ Isotopes were discovered long after Mendeleev had proposed periodic classification of elements. Isotopes of all elements posed a challenge to Mendeleev's Periodic Table. ⏩ Atomic mass do not increase in regular manner in going from one element to other.

I hope my answer helps you.....✌

Answer 2

Answer :-

The three achievements of Mendeleev's periodic table are :-

1. In Mendeleev's periodic table, the elements which have similar chemical properties are placed in similar groups. If we know the property or position of one element of that group, we can predict the properties of other elements of the same group.
2. Mendeleev left missing columns in his periodic table for unknown elements.
3. Mendeleev even predicted the chemical properties of elements that were not known at that time.

The two limitations of Mendeleev's periodic table are :-

1. Mendeleev placed Hydrogen in a group with alkali metals, but Hydrogen also resembles halogens.
2. Dissimilar elements were placed in the same group, while similar pairs of elements were placed in different groups. For eg. :- Cu and Hg have almost same properties, but they are placed in different groups.