Transition and Inner Transition Elements — Chemistry STD 12 Science — Question
Maharashtra BoardEnglish MediumSTD 12 ScienceChemistryTransition and Inner Transition Elements4 Marks
Question
Iron exhibits $+2$ and $+3$ oxidation states. Write their electronic configuration. Which will be more stable? Why?
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Answer
The electronic configuration of $Fe ^{2+}$ and $Fe ^{3+}$ :
$Fe^{2+}: Is^2 2 s^2 2 p^6 3 s^2 3 p^6 3 d^6$
$Fe ^{3+}$ : Is $s^2 2 s^2 2 p^6 3 s^2 3 p^6 3 d^5$ Due to loss of two electrons from the $4 . v$-orbital and one electron from the $3 d$-orbital, iron attains $3^{+}$oxidation state.
Since in
$Fe ^{3+}$, the 3 d -orbital is half-filled, it gets extra stability, hence $Fe ^{3+}$ is more stable than $Fe ^{2+}$.
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