Chemistry Transition Elements MDCAT 2014
PMDC Verified Question 61 of 68
Electronic configuration of manganese (Mn) is
A
\( Mn(Ar) \; 3d \; [\uparrow][\uparrow][\uparrow][\uparrow][\uparrow] \quad 4s \; [\uparrow\downarrow] \)
B
\( Mn(Ar) \; 3d \; [\uparrow\downarrow][\uparrow\downarrow][\uparrow][\uparrow][\uparrow] \quad 4s \; [\uparrow\downarrow] \)
C
\( Mn(Ar) \; 3d \; [\uparrow\downarrow][\uparrow\downarrow][\uparrow\downarrow][\uparrow][\uparrow] \quad 4s \; [\uparrow] \)
D
\( Mn(Ar) \; 3d \; [\uparrow\downarrow][\uparrow\downarrow][\uparrow\downarrow][\uparrow\downarrow][\uparrow\downarrow] \quad 4s \; [\uparrow] \)
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option A: \( Mn(Ar) \; 3d \; [\uparrow][\uparrow][\uparrow][\uparrow][\uparrow] \quad 4s \; [\uparrow\downarrow] \)
Concept:

Manganese (\(Mn\)) has an atomic number of 25. Its electron configuration follows the standard Aufbau principle filling order without anomalies.

Solution:

  • The nearest noble gas core is Argon (\(Ar\)), accounting for 18 electrons.


  • This leaves 7 valence electrons to be distributed in the \(4s\) and \(3d\) orbitals.


  • According to standard filling rules, the \(4s\) orbital fills first: \(4s^2\).


  • The remaining 5 electrons enter the \(3d\) orbitals singly (Hund's Rule): \(3d^5\).


  • Thus, the configuration is \([Ar] \; 3d^5 \; 4s^2\), which corresponds to 5 unpaired electrons in the 3d subshell and a paired 4s subshell.


Why other options are incorrect:

  • The other options represent incorrect electron counts or pair electrons prematurely, violating Hund's Rule of Maximum Multiplicity.

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