Question

Gd+3 ion stable why​

Answer 1

Answer: Because it has a stable half filled electronic configuration.

Explanation:

Gadolinium is the 64th element of the periodic table which belongs to the lanthanoid series.

The electronic configuration of Gd is: $[Xe]4f^75d^16s^2$

The electronic configuration of $Gd^{3+}$ is: $[Xe]4f^7$

As, this element looses 3 electrons making the oxidation state of +3, the element becomes stable because from the electronic configuration of $Gd^{3+}$, it is clearly visible that there are half-filled electrons in 4f-orbital.

And the configurations having half-filled and fully-filled orbitals are more stable.

Hence, it has a stable half filled electronic configuration.