How does inert pair effect arise?

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Explanation of Inert Pair Effect

The inert pair effect is a phenomenon in which the s-electrons of the outermost shell of an atom become less reactive than expected. This effect is observed in elements having oxidation states greater than +2. The inert pair effect is mainly observed in the heavier elements of groups 13, 14, 15, and 16 of the periodic table.

Causes of Inert Pair Effect

Electronegativity of the element: The inert pair effect is due to the increasing electronegativity of the element. As the atomic number increases in a group, the electronegativity of the element also increases. This results in the s-electrons being held more tightly by the nucleus, making them less available for bonding.

Screening effect of the d- and f-electrons: The s-electrons are screened from the nucleus by the d- and f-electrons. As the atomic number increases in a group, the number of d- and f-electrons also increases. This results in a stronger screening effect, which makes the s-electrons less available for bonding.

Effects of Inert Pair Effect

Lower oxidation states are more stable: Due to the inert pair effect, the lower oxidation states of the element are more stable than the higher oxidation states. For example, lead (Pb) has a +2 oxidation state that is more stable than the +4 oxidation state.

Decreased reactivity: The inert pair effect results in a decreased reactivity of the s-electrons. This makes it more difficult for the element to form bonds and undergo chemical reactions.

Applications of Inert Pair Effect

Manufacturing of lead-acid batteries: The inert pair effect is used in the manufacturing of lead-acid batteries. Lead has a stable +2 oxidation state, which makes it suitable for use in batteries.

Pharmaceutical industry: The inert pair effect is also used in the pharmaceutical industry. Many drugs are designed to target specific enzymes or proteins in the body. The inert pair effect can be used to modify the reactivity of these drugs, making them more effective.

Answer

Inert pair effect arises due to the inner d- or f- orbital which has lower shielding effect. Hence the effective nuclear charge increases. And so the outer s- orbital electrons are strongly hold by the attractive force of nucleus and thus they cannot take part in valence or bond formation and behaves as 'inert electrons'. This is called inert pair effect..hope it was useful :-) :-)

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