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.
