Question

Write any two demerits of Mandeleev's periodic table.​

Answer 1

Explanation:

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. Later on, isotopes of elements were found which violated Mendeleev's periodic law.

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Answer 2

Any two demerits of Mendeleev's Periodic Table aRe :

• Position of isotopes :

As Mendeleev's Periodic table is based on atomic weight , isotopes would have to be placed in different position . But it was not done.

• Position of Hydrogen :

Hydrogen iS placed in Group l A ( Alkali metals ) , but it has the property similar to Group VII A ( halogens ) . Thus position of hydrogen is still controversial.

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