The third ionization enthalpy is minimum for :
Solution
Electronic configuration of
<br><br><sub>25</sub>Mn = [Ar]3d<sup>5</sup>4s<sup>2</sup>
<br><br><sub>25</sub>Mn<sup>2+</sup> = [Ar]3d<sup>5</sup>4s<sup>0</sup>
<br><br><sub>26</sub>Fe = [Ar]3d<sup>6</sup>4s<sup>2</sup>
<br><br><sub>26</sub>Fe<sup>2+</sup> = [Ar]3d<sup>6</sup>4s<sup>0</sup>
<br><br><sub>27</sub>Co = [Ar]3d<sup>7</sup>4s<sup>2</sup>
<br><br><sub>27</sub>Co<sup>2+</sup> = [Ar]3d<sup>7</sup>4s<sup>0</sup>
<br><br><sub>28</sub>Ni = [Ar]3d<sup>8</sup>4s<sup>2</sup>
<br><br><sub>28</sub>Ni<sup>2+</sup> = [Ar]3d<sup>8</sup>4s<sup>0</sup>
<br><br>So third ionisation energy is minimum for Fe.
About this question
Subject: Chemistry · Chapter: Periodic Table and Periodicity · Topic: Periodic Trends
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