Different between mendeleev's periodic table and modern periodic table is:
| S.N | Mendeleev's Periodic Table | S.N | Modern Periodic Table |
| 1. | Elements are arranged in order of increasing atomic mass. | 1. | Elements are arranged in order of increasing atomic number. |
| 2. | There are nine vertical columns called groups. | 2. | There are eighteen vertical columns called groups. |
| 3. | Transition elements are arbitrarily placed together in group VIII. | 3. | Transition elements are placed in the middle of long periods. |
| 4. | There are some gaps for undiscovered elements. | 4. | There are no any gaps for the new elements. |
| 5. | There is not proper place for the inert gases. | 5. | The inert gases are arranged in zero group, extremely in left side of the periodic table. |
