Question

explain the drawback of Mendeleev's periodic table

Answer 1

HI !

Drawbacks/Demerits of Mendeleev's periodic table :-

1) Hydrogen's position
Hydrogen resembled the properties of both alkali metals(like lithium) and also that of halogens(like iodine). Hence, the position of hydrogen(whether hydrogen is to be placed with halogens or alkali metals) was not specified.

2) Position for Isotopes
Isotopes are those with same atomic no: and different mass no:s.
Mendeleev's periodic table was based on arranging elements in increasing order of atomic masses. But isotopes were not included in his periodic table.

3) Certain elements were arranged in reverse order. Elements having higher atomic mass were placed in front(or before) the elements with less atomic mass. Example - Cobalt and Nickel
Cobalt being more heavier than Nickel ,was placed before Nickel , in the Mendeleev's periodic table.

Hope this helps you !

Answer 2

ꃅꍟꋪꍟ  ꀤꌗ  ꌩꂦꀎꋪ  ꍏꈤꌗꅏꍟꋪ.... 

⏩ 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.

✨✔️HOPE IT HELPS YOU....
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