Question

write down the defect in mandeleev's periodic classification​

Answer 1

Answer:

Hope it helps u

Good evening♥♥

Answer 2

Answer:

Following are the defects in the Mendeleev periodic table:

1. Anomalous Pairs: The following pairs of elements don’t follow the follow Mendeleev’s Principles:

• Mendeleev’s Principles:Cobalt (58.9) with a higher atomic mass precedes Nickel (58.6) in the periodic table.
• Mendeleev’s Principles:Cobalt (58.9) with a higher atomic mass precedes Nickel (58.6) in the periodic table.Tellurium (127.6) with a higher atomic mass than Iodine (126.9) precedes it in the periodic table.

2.Grouping of chemically dissimilar elements: Elements such as Copper and Silver bear no resemblance with the alkali metals, but they have been placed together in the first group.

3.Position of Isotopes: According to Mendeleev’s Periodic Law, isotopes of an element must be given separate places in the periodic table because they have different atomic masses.

4.Electronic arrangement: It does not explain the electronic arrangement of elements.

5.Separation of chemically similar elements: Elements that are chemically similar such as Gold and Platinum have been placed in separate groups.

6.The position of hydrogen: Hydrogen was not given a fixed position because it was considered in Group IA as well as in Group VIIA.

I hope it will help you.