Mention Anomalies of Mendeleev 's periodic table.

Explanation

Some elements with similar properties were placed in different groups whereas some elements having dissemilar properties were placed in same group.
Eg : Tellurium (127.6) was placed in VI group but iodine (127.0) was placed in VII group.
Some elements with higher atomic weights were placed before lower atomic masses in order to maintain the similar chemical nature of elements.
This concept was called inverted pair of elements concept . Eg : `._(27)^(59)Co " "._(28)^(58.7)Ni`
Isotopes did not find any place in Medeleev's periodic table.
Position of hydrogen could not be made clear.
He did not leave any space for lanthanides and actinides which were discovered later on.
It could not explain the variable valencies of elements.
Elements with different nature were placed in one group as A and B '. Eg : Alkali metals & coinage metals were placed together.
Diagonal and horizontal relationships were not explained .