Question

The electronic configuration of Cu(II) is 3d9 whereas that of Cu(I) is 3d10. Which of the following is correct? [NCERT Exemplar]
(a) Cu(II) is more stable
(b) Cu(II) is less stable
(c) Cu(I) and Cu(II) are equally stable
(d) Stability of Cu(I) and Cu(II) depends on nature of copper salts

Answer 1

Option A is the correct answer.

• Half-filled and filled orbitals are extra stable than incompletely filled orbitals.
• Cu(II) is more stable than Cu(I) because it possesses a 2+ charge and is minor than Cu(I).
• The electron density and effective nuclear charge are considerable for Cu(II) and it constructs powerful bonds that contain high hydration energy and discharges more energy and is more stable.
• Energy is employed to eliminate one electron from Cu+ to Cu2+, and the high hydration energy of Cu2+ compensates for it. Accordingly, Cu+ion in an aqueous solution is unstable, so disproportionates to give Cu2+ and Cu.

Hence, Cu(II) is more stable and options A is the correct answer.

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