Four successive members of the first row transition elements are listed below with their atomic number. Which one of them is expected to have the highest third ionisation enthalpy ?

Options

A. Vanadium `(Z= 23)`
B. Chromium `(Z = 24)`
C. Manganese `(Z = 25)`
D. Iron `(Z = 26)`

Answer

C

Explanation

Removal of third electron from `._(25)Mn (3 d^(5) 4 s^(2))` takes place from half-filled orbitals of `Mn^(2+) (3d^(5))` ions. Also major energy shell changes.