Question

Modification in Mendeléey's Periodic Table​

Answer 1

Answer:

So it didn't explain the position of isotopes and many empty spaces were present but later after the discovery of atomic number by Moseley in 1911, Mendeleev's periodic table was improved by arranging the elements in ascending order of their atomic numbers instead of their atomic masses.

Answer 2

Answer:

Modified version of Mendeleev's Periodic Table : The elements which were undiscovered and for whom Mendeleev had left vacant places were discovered later. These elements, called noble gases, were placed in the table as a separate group, called 0 group. ...

Explanation:

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