Question

Assertion $N{a}^{+}$ and $A{l}^{3+}$are isoelectronic but the magnitude of ionic radius of $A{l}^{3+}$ is less than that of $N{a}^{+}$.
Reason The magnitude of effective nuclear charge of the outer shell electrons in $A{l}^{3+}$ is greater than that in $N{a}^{+}$.

• A. Both Assertion and Reason are true and Reason is the correct explanation of Assertion.
• B. Both Assertion and Reason are true but Reason is not the correct explanation of Assertion.
• C. Assertion is true but Reason is false.
• D. Both Assertion and Reason are false.

Answer 1

Answer: (A)

In case of isoelectronic species, effective nuclear charge increases with increase in atomic number, $Z$ (with increase in protons) This results in decrease in size Hence. ionic radius of $A{l}^{3+}<N{a}^{+}$