Question

what are the advantages and defects of mendeleev's periodic table ?

Answer 1

Answer:

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Disadvantages

He couldn't allocate a correct position to hydrogen. Atomic masses didn't increase in a regular manner, so it was impossible to predict how many elements could be discovered between two elements.

Advantage

• New elements have been discovered with the help of periodic table.
• Periodic table systamatises the study of elements and their compounds. ...
• It is possible to predict the properties of an element from the position of element in the periodic table.

Answer 2

Advantages

(a) He left some spaces in his periodic table and boldly predicted the existence of few elements like silicon, germanium and gallium.

(b) When noble gases were discovered can be kept in a separate group without disturbing the existing order.

Defects

(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 less than nickel

was placed before nickel.