give the anomalies of mendeleevs periodic table.
Answers
Anomalies of mendeleev's periodic table :-
1. Position of isotopes :- There is no place for isotopes in mendeleev's periodic table.
2. Position of hydrogen :- Mendeleev could not decide where to place hydrogen because it has properties of both - alkali metals and halogens.
3. Like atoms were placed in different groups :- There were some elements which have similar properties but they were placed in different groups in Mendeleev's periodic table. For example :- Pt and Au.
4. Unlike elements were placed in same group :- There were some elements which have different properties but they were placed in same group. For example :- Li , Cu ,etc.
5. Anomalous Pairs of element :- There were some pairs of elements which did not follow the increasing order of atomic weight. For example :- Ar and K.