Assertion (A): Mendeleev arranged element in horizontal rows and vertical columns.

Reason (R): Mendeleev ignored the order of atomic weight thinking that the atomic measurements might be incorrect.

 

Answer

In his periodic table, Mendeleev arranged elements in horizontal rows and vertical columns

He ignored the atomic weight while arranging atoms thinking that the atomic measurements may be incorrect.

In Mendeleev’s periodic table, elements having similar properties were kept together.  

Thus,

  • Assertion is true.
  • Reasoning is true.
  • The reasoning is not the correct explanation for assertion.

Therefore, the correct option is (b) Both assertion and reason are correct but reason is not the correct explanation for the assertion.

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CA Maninder Singh is a Chartered Accountant for the past 14 years and a teacher from the past 18 years. He teaches Science, Economics, Accounting and English at Teachoo