Question

The atomic numbers of vanadium chromium manganese and iron are respectively 23 24 25 and 26 which one of these may be expected to have the highest second ionization enthalpy

Answer 1

to know the highest second ionization enthalpy.

first write the electronic configuration of elements.

vanadium-(23)→ 2,8,8,5

chromium-(24)→ 2,8,8,6

manganese-(25)→ 2,8,8,7

iron-(26)→ 2,8,8,8

after first ionisation enthalpy

electronic configuration of elements will be

vanadium- 2,8,8,4

chromium-2,8,8,5

manganese- 2,8,8,6

iron- 2,8,8,7

iron will have highest first ionisation enthalpy because it had full filled shell and half filled shells and full filled shells are most stable.
and they require more energy.

for second ionization enthalpy
vanadium has half filled shell and as i mentioned above half filled and full filled shells are most stable .
so it will be difficult for vanadium to lose electron.
therefore more energy will be used .

hence vanadium will have highest second ionisation enthalpy.

hope it helps you

Answer 2

Answer:it should be chromium

Explanation:as it has a configuration [Ar]3d^5 4s^1