Transition elements are usually characterised by variable oxidation st...
Fully pilled d-subshell
Zn →Zn2+ + 2e-
3d104s2 3d10
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Transition elements are usually characterised by variable oxidation st...
The Characteristic of Transition Elements
Transition elements are a group of elements that are characterized by their ability to exhibit variable oxidation states. This means that they can exist in different charges or oxidation states depending on the reaction they are involved in. This property is due to the presence of unpaired electrons in their d orbitals, which allows for the formation of multiple bonding arrangements.
Explanation of the Correct Answer
The correct answer to the question is option 'B', which states that zinc (Zn) does not show variable oxidation states because of the completion of (n-1) d orbitals. This answer is correct because zinc is an exception among the transition elements due to its completely filled d orbitals.
Completion of (n-1) d Orbitals
Zinc belongs to the 3d transition series and its electron configuration is [Ar] 3d10 4s2. In this configuration, the 3d orbitals are completely filled with 10 electrons. Since the d orbitals are the ones responsible for variable oxidation states, the completion of the 3d orbitals in zinc prevents it from exhibiting different oxidation states.
Loss of Variable Oxidation States
The completion of the (n-1) d orbitals in zinc results in the loss of variable oxidation states because there are no unpaired electrons available for bonding. In transition elements, the presence of unpaired electrons in the d orbitals allows for the formation of multiple bonding arrangements, leading to the ability to exhibit variable oxidation states. However, when the d orbitals are completely filled, as in the case of zinc, there are no unpaired electrons available for bonding, and therefore, no variable oxidation states can be shown.
Inert Pair Effect
Option 'D' states that the lack of variable oxidation states in zinc is due to the inert pair effect. The inert pair effect refers to the tendency of the s electrons of the heavier main group elements to remain unreactive and not participate in bonding. While the inert pair effect does occur in some elements, it is not the reason for the lack of variable oxidation states in zinc. Instead, it is the completion of the (n-1) d orbitals that causes this property in zinc.
Conclusion
In conclusion, option 'B' is the correct answer because zinc does not show variable oxidation states due to the completion of its (n-1) d orbitals. The presence of completely filled d orbitals in zinc prevents the formation of multiple bonding arrangements and therefore eliminates the ability to exhibit variable oxidation states.