Question

The electronic configuration of $Cu\left(II\right)$ is $3d^9$, whereas that of $Cu\left(I\right)$ is $3d^{10}.$ Which of the following is correct?

• A. $Cu\left(II\right)$ is more stable
• B. $Cu\left(I\right)\text{and}Cu\left(II\right)$ are equally stable
• C. Stability of $Cu\left(I\right)$ and $Cu\left(II\right)$ depends on nature of copper salts
• D. $Cu\left(II\right)$ is less stable

Answer 1

The correct option is A $Cu\left(II\right)$ is more stable

The electronic configuration of $Cu\left(I\right)$ is

$\left[Ar\right]3d^{10}.$

The electronic configuration of $Cu\left(II\right)$ is

$\left[Ar\right]3d^9.$

The stabilities of the ions depend on their hydration energies released when the ions get linked to the water molecules.

$Cu\left(II\right)$ ion has a smaller size and a greater charge. So, it has a higher charge density compared to $Cu\left(I\right)$ ion.

Therefore, $Cu\left(II\right)$ ion gets linked to water molecules more strongly, which results in the release of more hydration energy as compared to $Cu\left(I\right)$ ion. Hence, $Cu\left(II\right)$ is more stable than $Cu\left(I\right).$

Thus, option $\left(A\right)$ is the correct answer