Question
Why is long form periodic table regarded better than the Mendeleev's periodic table?
Solution
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. |
