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

Answer 1

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

There is a general trend that half filled and completely filled orbitals are more stable than incompletely filled orbitals

Cu(II) is more stable than Cu(I) because it has a 2+ charge and is smaller than Cu(I).

The electron density and effective nuclear charge is greater for Cu(II) and it forms stronger bonds(high hydration energy) and releases more energy and is more stable.

Hence $Cu\left(II\right)$ is more stable than $Cu\left(I\right)$.