Question

write the Demerits of mendenellv s pérodic table​

Answer 1

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• He was unable to locate hydrogen in the periodic table.
• Increase in atomic mass was not regular while moving from one element to another. ...
• Later on, isotopes of elements were found which violated Mendeleev's periodic law.

Answer 2

Answer:

The demerits or drawbacks of Mendeleeve's periodic table were:

• 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.

• Elements having different properties were placed in the same sub group like manganese (Mn) was placed with halogens which had totally different properties
• Elements of higher atomic mass were placed before elements of lower atomic mass. Cobalt with atomic mass 58.93 was placed before nickel with atomic mass 58.71.

• Isotopes had to be given the same position in the periodic table though isotopes of the same elements have different atomic masses.