Q.1) Give merits and demerits of Mendeleev's periodic table.
Answers
▪There was a regular gradation in physical and chemical properties of elements.
▪The group number of an element indicates highest oxidation state that it can attain.
▪There were many vacant spaces in Mendeleev's periodic table for the elements to be discovered.
Answer:
Merits of Mendeleev's Periodic Table:
⋅ Mendeleev was first to properly arrange and classify all elements and was able to explain the periodicity in their chemical properties.
⋅ Mendeleev left some gaps for undiscovered elements. He predicted that some elements would be discovered in future. He also predicted properties of those undiscovered elements.
Demerits of Mendeleev's Periodic Table:
⋅ Position of hydrogen was not justified.
⋅ Increasing order of atomic mass could not be maintained throughout the table.
⋅ There is no place for isotopes.
Explanation:
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