Question

Cuprous ion is colourless while cupric ion is coloured because ______.

विकल्प

• both have half filled p-and d-orbitals

• cuprous ion has incomplete d-orbital and cupric ion has a complete d-orbital

• both have unpaired electrons in the d-orbitals

• cuprous ion has complete d-orbital and cupric ion has an incomplete d-orbital.

Answer 1

Cuprous ion is colourless while cupric ion is coloured because cuprous ion has complete d-orbital and cupric ion has an incomplete d-orbital.

Explanation:

Cu+ has the configuration [Ar] 3d10 (filled d‑shell) so no low‑energy d → d transitions and it is usually colourless. Cu2+ is [Ar] 3d9 (partially filled d‑orbitals), allowing d–d electronic transitions (and often Jahn–Teller distortions) that absorb visible light and give coloured compounds.