Question

Assertion :In any transition series, the magnetic moment of $M^{2+}$ ion first increases and then decreases. Reason: In any transition series, the number of unpaired electrons first increases, afterwards decrease.

• A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
• B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
• C. Assertion is correct but Reason is incorrect
• D. Both Assertion and Reason are incorrect

Answer 1

The correct option is A Both Assertion and Reason are correct and Reason is the correct explanation for Assertion

The magnetic moment of an element depends on a number of unpaired electrons. As the number of unpaired electrons increases the magnetic moment increases as the number of unpaired electrons decreases the magnetic moment decreases so in transition elements number of unpaired electrons first increases and then decreases.

So, in any transition series, the magnetic moment of $M^{+2}$ ion first increases and then decreases.

Both assertion and reason are correct and the reason is the correct explanation for the assertion.

Hence, option $A$ is correct.