Question

state the merits and demerits of mendeleev's periodic table
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Answer 1

Answer: merits of mandeleev periodic table :

1) He left spaces for other elements which would be discover in future.

2)He named the elements like eka aluminum , eka silicon for elements to be discovered after them.

3)there was regular gradation of physical and chemical properties of elements.

4) he arranged them in groups and periods.

Demerits

1) no fixed position of isotopes.

2) no fixed place of hydrogen in his table.

3) anomalous position of some elements .

Answer 2

Answer:

merits-

1 nobal gasses were placed in the last group without disturbing other elements

2 he said that some elements will discovered later on and he named them by their preceding elements.

For example-

eka aluminium-gallium

eka boron-scandium

eka silicon-germanium

demerits

1 hydrogen does not have fixed place

2 no place for isotopes

3 cobalt was placed before nickle which has higher atomic mass