Q1(j). Transition elements and CuCl

Answer in brief

A transition element has an incomplete d subshell in its atom or can form a cation with an incomplete d subshell. CuCl is a compound of the transition element copper, though Cu(I) itself is d¹⁰.

Key points

• Copper forms Cu(II), 3d⁹, and therefore qualifies as a transition element.
• In CuCl, copper is Cu(I), with filled 3d¹⁰. It consequently lacks the unpaired d electrons and ordinary d–d transitions associated with many transition-metal ions.
• Distinguish classification of the element from the electronic configuration in one compound. A d¹⁰ oxidation state does not reclassify copper as a non-transition element.