1. Tardigrade
  2. Question
  3. Chemistry
  4. The atomic number of V, Cr, Mn and Fe are respectively 23, 24, 25 and 26.Which one of these may be expected to have the highest second ionisation enthalpy ?

Question Error Report

Thank you for reporting, we will resolve it shortly

Back to Question

Q. The atomic number of V, Cr, Mn and Fe are respectively 23, 24, 25 and 26.Which one of these may be expected to have the highest second ionisation enthalpy ?

AIEEEAIEEE 2003The d-and f-Block Elements

Solution:

Outer electronic configurations of V, Cr, Mn and Fe are as follows.
$V(4s^2 3d^3), Cr(4s^1 3d^5), Mn(4s^23d^5), Fe(4s^23d^6)$
Outer electronic configuration of uni-positive ions are
$V^+(4s^13d^3), Cr^+ (3d^5), Mn^+(4s^13d^5), Fe^+ (4s^13d^6)$
Clearly, I.$E_2$ of Cr will be highest as $Cr^+$ has exactly half filled $d$-subshell.