drawback of modern periodic table
Drawbacks of modern periodic table:
1.Hydrogen resembles both the alkali metals and halogens But it has been placed with the alkalis.
2.The lanthanides and actinides have not been placed in the main body of the table.
3.Place of Multivalent elements is not sure in the modern periodic table.
1. Although most of the elements were placed in the order of increasing atomic weights but this increasing order could not be maintained in all cases. For example - Cobalt atomic mass is 58.93u preceded Nickel 58.71u preceded Tellurium 127.6 preceded Iodine 126.90, thus he couldnt maintain similarities in properties.
2. Mendeleev periodic table did not provide space for noble gases which were discovered later.
3. Moreover there was no space left for isotopes in medeleev 's periodic table.