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Classification of Elements and Periodicity in Properties — Chemistry STD 11 Science — Question

Gujarat BoardEnglish MediumSTD 11 ScienceChemistryClassification of Elements and Periodicity in Properties5 Marks
Question
What is the basic difference in approach between the Mendeleev’s Periodic Lawand the Modern Periodic Law?
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Answer

According to Mendeleev’s periodic law, the physical and chemical properties of the elements are periodic functions of their atomic masses, but according to modern periodic law, the physical and chemical properties of the elements are periodic functions of their atomic numbers.

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1. Suggest a method to purify
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\begin{aligned}
& HS^{-}, BF_3, C_2 H_5 O^{-},\left(CH_3\right)_3 N:, \\
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