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| 1. |
Droback Mendleev\'s\' periodic table |
| Answer» Draw-backs of mendeleev \'s periodic table : (i) position of hydrogen was not justified. (ii) there was no space left for isotope in his table. (iii) some elements having higher atomic masses were placed before those having lower atomic masses (for example, CO with higher atomic mass placed before Ni having lower atomic mass) (iv) two similar elements like Cu and Hg were grouped differently (v) the position of actinoids and lanthanides were not included in this table. | |