The key difference between inert pair effect and shielding effect is that inert pair effect is the ability of a pair of electrons in the outermost electron shell to remain unchanged in post-transition metal compounds, whereas shielding effect is the reduction of the attraction force between electrons and atomic nucleus in an atom.
Inert pair effect and shielding effect are two different phenomena discussed in chemistry. Both these terms describe the attraction force between electrons and the atomic nucleus.
CONTENTS
1. Overview and Key Difference
2. What is Inert Pair Effect
3. What is Shielding Effect
4. Side by Side Comparison – Inert Pair Effect vs Shielding Effect in Tabular Form
5. Summary
What is Inert Pair Effect?
Inert pair effect is the tendency of the outermost electrons in an atom to remain unchanged when forming a compound. It happens mostly with the outermost electrons that are in the s atomic orbital, and we can observe it in post-transition metals. These electrons remain unshared or unionized when forming the compound because these outermost s electrons are more tightly bound to the atomic nucleus. Furthermore, this term is mostly used with heavier elements such as those in group 13, 14, 15, and 16. Also, this theory about the inert pair effect was first introduced by the scientist Nevil Sidgwick in 1927.
Figure 01: Atomic Radius Affects the Inert Pair Effect
For example, let us consider the chemical element Thallium in group 13. The +1 oxidation state of this chemical element is stable, but the +3 oxidation state is unstable and rare. When the stability of +1 oxidation states of the other chemical elements in the same group is considered, thallium has the highest stability due to this inert pair effect.
What is Shielding Effect?
Shielding effect is the reduction of the attraction force between electrons and atomic nucleus in an atom, which reduces the effective nuclear charge. The synonyms for this term are atomic shielding and electron shielding. It describes the attraction between electrons and atomic nucleus in atoms containing more than one electron. Therefore, it is a special case of electron-field screening.
Figure 02: Effective Nuclear Charge
According to this shielding effect theory, the wider the electron shells are in space, weaker the electric attraction between electrons and the atomic nucleus.
What is the Difference Between Inert Pair Effect and Shielding Effect?
Inert pair effect and shielding effect are two different phenomena discussed in chemistry. The key difference between inert pair effect and shielding effect is that inert pair effect is the ability of a pair of electrons in the outermost electron shell to remain unchanged in post-transition metal compounds, whereas shielding effect refers to the reduction of the attraction force between electrons and atomic nucleus in an atom.
Moreover, a further difference between inert pair effect and shielding effect is that the inert pair effect occurs in heavier chemical elements such as group 13, 14, 15 and 16 elements, while the shielding effect occurs in chemical elements with many electrons.
Summary – Inert Pair Effect vs Shielding Effect
Inert pair effect and shielding effect are two different phenomena discussed in chemistry. The key difference between inert pair effect and shielding effect is that inert pair effect is the ability of a pair of electrons in the outermost electron shell to remain unchanged in post-transition metal compounds, whereas shielding effect refers to the reduction of the attraction force between electrons and atomic nucleus in an atom.
Reference:
1. “Inert Pair Effect.” Wikipedia, Wikimedia Foundation, 24 Jan. 2020, Available here.
2. Mott, Vallerie. “Introduction to Chemistry – The Shielding Effect and Effective Nuclear Charge.” Lumen, Available here.
Image Courtesy:
1. “D-block contraction–EN” By Armando-Martin – Own work (CC BY-SA 3.0) via Commons Wikimedia
2. “Effective Nuclear Charge” By Own work – Effective Nuclear Charge.gif (CC0) via Commons Wikimedia