| Mendeleev’s periodic table | Modern periodic table |
| i | This table is based on the atomic mass of the elements. | This table is based on the atomic number of the elements. |
| ii | Elements are arranged in increasing order of their atomic mass. | Elements are arranged in increasing order of their atomic number. |
| iii | It is not divided into any blocks. | It is divided into four blocks, namely sblock, p-block, dblock and f-block. |
| iv | Inert elements are not mentioned. | Inert elements are mentioned. |
| v | There are 8 groups. | There are 18 groups. |
| vi | There are 7 periods. | Apart from 7 periods there are two extra additional rows placed separately at the bottom of modern periodic table. |
