Actinoids show larger number of oxidation states:

Question

Statement-I : Consider the following pairs of ions $(\text{Sc}^{3+}, \text{Ti}^{3+}), (\text{Ti}^{4+}, \text{Ni}^{2+}), (\text{Cu}^{2+}, \text{Zn}^{2+})$ and $(\text{Cr}^{3+}, \text{Mn}^{3+})$. Out of these pairs three pairs consist of ions that are both coloured :
Statement-II : Among the lanthanide ions $\text{Eu}^{2+}$, $\text{Gd}^{3+}$, $\text{Ce}^{4+}$ and $\text{Tb}^{4+}$, the ion $\text{Tb}^{4+}$ is the strongest reducing agent.
Choose the correct option.

Answer 1

To understand why actinoids show a large number of oxidation states, we need to consider their electronic configuration and the nature of their orbitals.

Actinoids are elements with atomic numbers from 89 (actinium) to 103 (lawrencium) and belong to the f-block of the periodic table. The distinguishing feature of actinoids is their ability to exhibit a wide range of oxidation states, which is primarily due to the following reason:

Actinoids have 5f, 6d, and 7s orbitals that are very close in energy.

This feature allows electrons to be relatively easily removed from or added to these orbitals, contributing to various oxidation states. Let's examine the principles involved:

Electronic Configuration: The outer electron configuration of actinoids involves the filling of 5f, 6d, and 7s orbitals. Due to their extensive wavefunctions, these orbitals can overlap significantly with the s and d orbitals, allowing for various electronic arrangements.
Energy Levels: The energies of 5f, 6d, and 7s orbitals are comparable, meaning that small changes in the chemical environment can easily lead to different electron arrangements. This leads to multiple stable or partially stable oxidation states.
Electropositive Nature: While the electropositive nature of actinoids contributes to their reactivity, the variety of oxidation states is primarily due to the closely related energy levels of 5f, 6d, and 7s orbitals.
Atomic Number and Size: Although they have large atomic numbers and sizes, these characteristics are not the primary reasons for the variety of oxidation states. The decisive factor is the similarity in orbital energy levels.

Therefore, the correct answer is that actinoids show a larger number of oxidation states due to the comparable energies of 5f, 6d, and 7s orbitals, which allows for various stable electronic arrangements.

Answer 2

To understand why actinoids show a large number of oxidation states, we need to consider their electronic configuration and the nature of their orbitals.

Actinoids are elements with atomic numbers from 89 (actinium) to 103 (lawrencium) and belong to the f-block of the periodic table. The distinguishing feature of actinoids is their ability to exhibit a wide range of oxidation states, which is primarily due to the following reason:

Actinoids have 5f, 6d, and 7s orbitals that are very close in energy.

This feature allows electrons to be relatively easily removed from or added to these orbitals, contributing to various oxidation states. Let's examine the principles involved:

Electronic Configuration: The outer electron configuration of actinoids involves the filling of 5f, 6d, and 7s orbitals. Due to their extensive wavefunctions, these orbitals can overlap significantly with the s and d orbitals, allowing for various electronic arrangements.
Energy Levels: The energies of 5f, 6d, and 7s orbitals are comparable, meaning that small changes in the chemical environment can easily lead to different electron arrangements. This leads to multiple stable or partially stable oxidation states.
Electropositive Nature: While the electropositive nature of actinoids contributes to their reactivity, the variety of oxidation states is primarily due to the closely related energy levels of 5f, 6d, and 7s orbitals.
Atomic Number and Size: Although they have large atomic numbers and sizes, these characteristics are not the primary reasons for the variety of oxidation states. The decisive factor is the similarity in orbital energy levels.

Therefore, the correct answer is that actinoids show a larger number of oxidation states due to the comparable energies of 5f, 6d, and 7s orbitals, which allows for various stable electronic arrangements.

Actinoids show larger number of oxidation states:

Show Hint

The Correct Option is D

Solution and Explanation

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