Question

Four successive members of the first row transition elements are listed below with their atomic numbers. Which one of them is expected to have the highest third ionization enthalpy :- ​

Answer 1

Answer:

Four successive members of the first row transition elements are listed below with their atomic numbers. Which one of them is expected to have the highest third ionization enthalpy? A) Vanadium (Z = 23)

Answer 2

$\displaystyle\underline{\bigstar\orange{\sf Question}}$

Four successive members of the first row transition elements are listed below with their atomic numbers. Which one of them is expected to have the highest third ionization enthalpy :-

(1) Vanadium (Z = 23)

(2) Manganese (Z = 25)

(3) Chromium (Z = 24)

(4) Iron (Z = 26)

$\displaystyle\underline{\bigstar\pink{\sf Answer}}$

✭ Manganese has the highest ionisation enthalpy.

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»» Generally across the period , ionisation energy increases except some places.

Half filled and completely filled orbital requires more energy to remove the electron from its orbit. Hence they have high ionisation energy.

»» Half filled d orbital has 5 electrons. It confers maximum stability.

➳ Vanadium electronic configuration is 3d³ 4s².

➳ Chromium electronic configuration is 3d⁵ 4s¹

➳ Manganese electronic configuration is 3d⁵ 4s²

➳ Iron electronic configuration is 3d⁶ 4s².

$\displaystyle\bullet\sf{\:Chromium}$

»» When it loses an electron from 4s orbital , it stablises by half filled 3d orbital. So it is easy to remove one electron. It has low ionisation enthalpy.

$\displaystyle\bullet\sf{\:Vanadium}$

»» When it loses an electron from 4s orbital , the configuration becomes 3d³4s¹. It is neither half filled nor completely filled. So ionisation enthalpy is relatively low.

$\displaystyle\bullet\sf{\:Iron}$

»» The removal of electron from 4s orbital has no dependence on its stability factor . Its ionisation enthalpy is also comparitively low.

$\displaystyle\bullet\sf{\: Manganese}$

»» It is already in half filled state. So it becomes difficult to remove the electron from its outer orbital. So its ionisation energy is much higher.

✪ Expected order of ionisation energy: V<Cr<Mn<Fe

✪ Correct order: V<Cr<Fe<Mn

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