Question

Which of the following metal is expected to have the highest third ionization enthalpy.

• A. $Cr\left(Z = 24\right)$
• B. $V\left(\right.Z=23\left.\right)$
• C. $Mn\left(\right.Z=25\left.\right)$
• D. $Fe\left(\right.Z=26\left.\right)$

Answer 1

Answer: (C)

$Mn$ had outer electronic configuration as $4s^{2}3d^{5}$ , first two electrons are removed from $4s-$ orbital, but the removal of $3^{r d}$ electron is from half filled $3d-$ orbital, which requires higher ionization energy then other metal.