Chemistry Transition Elements NUMS 2019
PMDC Verified Question 45 of 68
Valence electronic configuration \( Cu^{2+} \) is \( ^{29}Cu \)
A
\( 5d^{6} \)
B
\( 3d^{8} \)
C
\( 3d^{9} \)
D
\( 3d^{7} \)
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option C: \( 3d^{9} \)
Concept:

When transition metals form cations, electrons are first removed from the outermost \(s\)-orbital (highest principal quantum number \(n\)) before being removed from the inner \(d\)-orbitals.

Solution:

  • The ground state electron configuration of neutral Copper (\(Z = 29\)) is \([Ar] \; 3d^{10} \; 4s^1\).


  • To form the \(Cu^{2+}\) ion, two electrons must be removed.


  • First, the one electron in the \(4s\) orbital is removed (\(4s^0\)).


  • Next, one electron is removed from the \(3d\) orbital, leaving 9 electrons in the \(d\)-subshell.


  • The final valence configuration is \(3d^9\).


Why other options are incorrect:

  • The options \(3d^8\) and \(3d^7\) represent higher, non-standard oxidation states for copper (\(+3\) and \(+4\)).

Quality & Fidelity Assurance: Every question on BeambePrep is rigorously curated against the official PMDC syllabus with zero filler, zero out-of-syllabus content, and zero typos. When an authentic past paper originally contained a historical mistake or ambiguity from the examining board (such as UHS or NUMS), BeambePrep faithfully reflects the original paper while detailing the nuance and scientific consensus in the autopsy above.

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