The electronic configuration of Cu in +1 oxidation state is
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → [Ar] 3d10
Copper (Z = 29) has the configuration [Ar] 3d10 4s1, one of the exceptions where a completely filled 3d subshell is more stable than 3d94s2. When an atom of a transition element forms a cation, the 4s electron is lost first:
Cu [Ar] 3d104s1 → \( \ce{Cu^{+}} \) [Ar] 3d10 + e−
Why the other options are incorrect
Option (2) [Ar] 3d94s1 — Incorrect. Removes a 3d electron instead of the 4s electron.
Option (3) [Ar] 3d104s1 — Incorrect. The neutral Cu atom, with no electron removed.
Option (4) [Ar] 3d94s2 — Incorrect. Has 29 electrons and is not even the ground state of the atom.