Question

The reason for the stability of $G{d}^{3+}$ ion is

• A. 4f subshell-half filled
• B. 4f subshell-completely filled
• C. Possesses the general electronic configuration of noble gases
• D. 4f subshell empty

Answer 1

Answer: (A)

Gd (Z = 64) : $[Xe{]}^{54}4f^{7}5d^{1}6s^2$
$G{d}^{3+}:[Xe{]}^{54}4f^7$
$G{d}^{3+}$ is stable due to the presence of exactly half filled $4f$-subshell.