Question

(i) What are the demerits of Mendeleev's periodic table?​

Answer 1

Demerits of Mendeleev Periodic Table. He was unable to locate hydrogen in the periodic table. Increase in atomic mass was not regular while moving from one element to another. Hence, the number of elements yet to be discovered was not predictable.

Demerits of Mendeleev's Periodic Table :

(a) Mendeleev arranged elements in the ascending order of their atomic masses. There was no fixed position for hydrogen in his periodic table, as it resembled alkali metals as well as halogens.

(b) Elements of higher atomic mass were placed before elements of lower atomic mass. Cobalt with atomic mass 58.9358.93 was placed before nickel with atomic mass 58.7158.71.

(c) Elements having different properties were placed in the same sub group like manganese \left(Mn\right)(Mn) was placed with halogens which had totally different properties

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Answer 2

Answer:

✨here is your answer ✨

✨Advantage of Mendeleev Periodic Table :-1.He left blank  Places which help scientist to discover new element 2.When Noble gasses was discovered Hel could add  it to periodic table without any major changle 3.He predicted the property of new element Disadvantages :- 1. Couldn't explain position of Hydrogen  2.Couldn't answer the question "Can we have an element with atomic mass 3 between Hydrogen and Helium  3 He placed cobalt before Nickel though Cobalt has more mass..

✨Demerits of Mendeleev Periodic Table. He was unable to locate hydrogen in the periodic table. Increase in atomic mass was not regular while moving from one element to another. Hence, the number of elements yet to be discovered was not predictable.

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