Question

The values ${E^o}$ for ${\text{Mn}}$ and ${\text{Zn}}$ are more negative than expected because:
A.They have either half-filled and fully filled configurations
B.They can easily donate electrons
C.It is quite easy to remove electrons from their orbitals
D.None of the above

Answer 1

Hint: To answer this question, recall the concept of negative ${E^o}$ values. Elements which have less atomic repulsion will have negative values.

Complete step by step answer:
-The main reasons which cause increased stability of half-filled and fully orbitals are:
Symmetrical distribution: Nature loves symmetry as it leads to increased stability and less energy.
-Exchange energy: The electrons when present in their degenerate orbitals i.e. orbitals with the same energy with parallel spin have shown to exchange their position. The energy released by these exchanges is known as exchange energy. More the exchange of energy and more stability.
-Negative ${E^o}$ values of ${\text{Mn}}$ and ${\text{Zn}}$ are due to the same above two reasons as from the electronic configurations you can see they both show half-filled and fully filled orbitals respectively: \[_{25}Mn:{\left[ {Ar} \right]_{18}}3{d^5}4{s^2}\] and \[_{30}Zn:{\left[ {Ar} \right]_{18}}3{d^{10}}4{s^2}\].

Therefore, the correct answer to this question is option A.

Note:
The electronic configuration of elements is based on majorly 3 rules:
1.According to the Pauli exclusion principle in an atom, no two electrons will have an identical set or the same quantum numbers. There salient rules of Pauli Exclusion Principle are that only two electrons can occupy the same orbital and the two electrons that are present in the same orbital should be having opposite spins.
2.According to Hund’s Rule of Maximum Multiplicity rule for a given electronic configuration of an atom, the electron with maximum multiplicity falls lowest in energy.
3.According to Aufbau principle, the electrons will start occupying the orbitals with lower energies before occupying higher energy orbitals.