Electron Configuration for Lanthanides

[oliver2217]

Homework Statement

Explain why ytterbium and europium prefer the 2+ ionic state compare to the rest of the Lanthanides which prefer a 3+ ionic state.

The Attempt at a Solution

I understand why europium prefers the 2+ ionic state ( largest exchange energy), but when trying to explain ytterbium using the fact that it has the lowest Z(eff) due to the fact that electrons are poor shielders of other electrons in the same orbital I feel as though I void the argument for why the rest of the Lanthanides would want to lose an extra electron. Any ideas?

 

[nate808]

I can provide some insights into why ytterbium and europium prefer the 2+ ionic state compared to the rest of the Lanthanides. First, it is important to understand that the ionic state of an element is determined by the balance between its ionization energy and its electron affinity. In general, elements with low ionization energies and high electron affinities tend to form cations (positive ions), while those with high ionization energies and low electron affinities tend to form anions (negative ions).

In the case of the Lanthanides, the trend is for them to prefer a 3+ ionic state due to their relatively high ionization energies and low electron affinities. However, ytterbium and europium deviate from this trend due to their unique electronic configurations. Ytterbium has a half-filled f-orbital, which is known to provide extra stability to the element and make it more reluctant to lose an extra electron. This is supported by the fact that ytterbium has the lowest Z(eff) among the Lanthanides, as mentioned in the forum post.

On the other hand, europium has a fully-filled f-orbital, which also contributes to its stability and preference for the 2+ ionic state. Additionally, europium has a relatively low ionization energy and high electron affinity, making it more likely to form a cation.

Overall, the electronic configurations of ytterbium and europium play a significant role in their preference for the 2+ ionic state. It is also worth noting that other factors such as crystal field effects and coordination geometry can also influence the preferred ionic state of an element. I hope this helps to clarify why ytterbium and europium deviate from the trend of the rest of the Lanthanides in terms of their preferred ionic state.