Question

Atomic numbers of vanadium, chromium, nickel and iron are $23, 24, 28$ and $26$ respectively. Which one of these is expected to have the highest second ionization enthalpy?

• A. $Cr$
• B. $V$
• C. $Fe$
• D. $Ni$

Answer 1

Answer: (A)

$Cr$

Answer 2

Second ionization enthalpy of Cr is highest. because after the removal of $1^{st}$ electron, Cr acquires -a. stable half-filled $d^5$ configuration thus, removal of $2^{nd}$ electron is very difficult.