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प्रश्न
State the contributions made by Mendeleev towards the periodic table.
उत्तर
Contribution made by Mendeleev:
- Elements were arranged in increasing order of atomic weights in horizontal rows called periods in vertical columns called groups.
- Elements which are similar w.r.t. their chemical properties are grouped together and have atomic weights of nearly the same value.
- Elements in the same group had the same valency and similar chemical properties.
- The properties of undiscovered elements left in the vacant gaps were predicted.
- Incorrect atomic weights of some of the arranged elements were corrected with the knowledge of the atomic weights of the adjacent elements.
- Number of gaps were left in the table for elements not known at that time. Even predicted their properties by studying the properties of neighbouring elements. These elements were later on discovered and their properties were found to be corrected.
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