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Classification of Elements and Periodicity in Properties
Why is long form periodic table regarded better than the Mendeleev's periodic table?
Long form periodic table is regarded as better than the Mendeleev’s table due to the following reasons:
| Long form periodic table | Mendeleev's |
| 1. All elements have been arranged in the increasing order of atomic numbers. | 1. Elements have been arranged in the increasing order of atomic masses. |
| 2. The position of hydrogen has been justified. | 2. There is no justification for the position of hydrogen. |
| 3. It takes into consideration the filling of the electrons in s, p, d and f subshell. | 3. It takes into consideration only the atomic numbers of the element. |
| 4. The table has been divided into four blocks i.e. s, p, d and f block. | 4. There are no blocks in the table. |
| 5. Groups are not further sub-divided into subgroups. | 5. There are sub-groups (A and B) in each group. |
| 6. This is simple and easy to reproduce. | 6. This is quite difficult to reproduce. |
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Gallium was named by Mendeleev as
What are magic numbers?
Which property is the basis of long form of periodic table?
How many elements are placed in each period of the p-block?
What is the number of groups in: (i) p-block (ii) d-block?
How many elements are present in:
(i) second period
(ii) fourth period
(iii) sixth period?
What is the name given to the s-block elements?
To which block the element with outer electronic configuration 4s23d10 belongs?
Why are there 10 elements in each series of d-block?
In terms of electronic configuration,
what is common in a given period and group?
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