Question

The atomic number of vanadium (V), chromium (Cr), manganese (Mn) and iron (Fe) are respectively 23, 24, 25 and 26 which one of these may be expected to have the highest second ionization enthalpy

• A. V
• B. Cr
• C. Mn
• D. Fe

Answer 1

The correct option is B Cr

V = $1s^2,2s^2,2p^6,3s^2,3p^6,3d^3,4s^2$


Cr = $1s^2,2s^2,2p^6,3s^2,3p^6,3d^3,4s^1$


V = $1s^2,2s^2,2p^6,3s^2,3p^6,3d^5,4s^2$


Fe = $1s^2,2s^2,2p^6,3s^2,3p^6,3d^6,4s^2$

In second ionization enthalpy Cr${}^{+}$ has exact half filled d-sub shell.