Question

The anomalous pairs in Mendeleev’s periodic table is/are
A.Co, Ni
B.Te, I
C.Ar, K
D.All the above

Answer 1

According to Mendeleev, the chemical and physical properties of elements were related to their atomic mass in a periodic way. Anomalous pairs are the pairs of elements which atomic mass was not increasing. Some elements which have higher atomic weight were placed before low atomic weight.

Complete step by step answer:
This periodic table is the study of elements, which is useful to study and remember the property of a large number of elements.
As we know there are 118 elements in the periodic table. Periodic table invented by Mendeleev. The physical and chemical property in these elements are different. According to their natures, their properties are different from each other.
Here anomalous pairs in Mendeleev’s periodic table are found by the higher atomic weight of elements placed by the low atomic weight. They are in order to maintain chemical nature and they are called inverted pairs or anomalous pairs.
So, the pair of Mendeleev’s periodic tables are: $Ar - K,Co - Ni,Te - I$ .

Hence, option (D) is correct answer.

Note: Mendeleev’s periodic table is widely accepted, because he shows characteristics and placement of elements which are discovered. The physical and chemical properties of an element predict the properties of undiscovered elements. Mendeleev prepared periodic tables by using elements in order of increasing atomic mass. Here we remember that the first element has higher mass than the second element. So Anomalous pair of elements is depending on the mass.