Q. In $M$ is element of actinoids series, the degree of complex formation decreases in the order

A) $M^{4 +} > M^{3 +} > MO_{2}^{2 +} > MO_{2}^{+}$
B) $MO_{2}^{+} > MO_{2}^{2 +} > M^{3 +} > M^{4 +}$
C) $M^{4 +} > MO_{2}^{2 +} > M^{3 +} > MO_{2}^{+}$
D) $MO_{2}^{2 +} > MO_{2}^{+} > M^{4 +} > M^{3 +}$
Explanation

(b)
The higher the charge on the metal ion, smaller is the ionic size and more is the complex forming ability. Thus, the degree of complex formation decreases in the order
$M^{4 +} > MO_{2}^{2 +} > M^{3 +} > MO_{2}^{+}$
The higher tendency of complex formation of $MO_{2}^{2 +}$ as compared to $M^{3 +}$ is due to high concentration of charge on metal atom $M$ in $MO_{2}^{2 +}$

Dr. Abubacker
Reviewed by Dr. Abubacker

Physics Educator & NEET/JEE Specialist

Ph.D. in Physics with 19+ years of teaching experience.