Chemistry Transition Elements MDCAT 2016
PMDC Verified Question 57 of 68
The anomalous electronic configuration shown by chromium and copper among 3-d series of elements is due to:
A
Colour of ions of these metals
B
Variable oxidation states of metals
C
Complex formation tendency of metals
D
Stability associated with this configuration
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option D: Stability associated with this configuration
Concept:

The shifting of electrons to form anomalous electron configurations is driven purely by the system seeking the lowest possible energy state, which yields maximum thermodynamic stability.

Solution:

  • Half-filled subshells (like \(3d^5\) in Chromium) and completely filled subshells (like \(3d^{10}\) in Copper) possess enhanced symmetrical electron distribution.


  • This symmetry minimizes electron-electron repulsion and maximizes exchange energy, granting these configurations superior thermodynamic stability compared to \(d^4\) or \(d^9\).


Why other options are incorrect:

  • Colour, variable oxidation states, and complex formation are physical and chemical consequences or properties of transition metals, not the fundamental quantum mechanical cause of their ground-state electron filling anomalies.

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