Problem 124 - A Complete Resource Book in Chemistry for JEE Main

Question

Match the following: \(\begin{array}{ll}\text { List I } & \text { List II }\end{array}\) (Hydridization) \(\quad\) (Geometry of the molecule) 1\. \(\mathrm{sp}^{2}\) (i) trigonal bipyramidal 2\. \(\mathrm{sp}^{3}\) (ii) planar trigonal 3\. sp (iii) octahedral 4. (iv) tetrahedral (v) linear The correct matching is: \(\begin{array}{lll}1 & 2 & 3\end{array}\) 4 (a) (ii) (iv) (v) (i) (b) (iii) (v) (i) (vi) (c) (iv) (iii) (i) (ii) (d) (vi) (ii) (v) (iii)

Step-by-Step Solution

Answer

The correct matching is option (a): \((\text{ii}, \text{iv}, \text{v})\).

Step 1: Understand Hybridization Types

The term 'hybridization' refers to the mixing of atomic orbitals to form new hybrid orbitals suitable for the pairing of electrons to form chemical bonds. Different hybridizations correspond to different molecular geometries: \( \text{sp}^2 \), \( \text{sp}^3 \), and \( \text{sp} \) all match to specific geometrical shapes.

Step 2: Match Each Hybridization to Geometry

Identify the geometry associated with each type of hybridization:1. \( \text{sp}^2 \) hybridization leads to a planar trigonal shape, which is option (ii).2. \( \text{sp}^3 \) hybridization leads to a tetrahedral shape, which is option (iv).3. \( \text{sp} \) hybridization results in a linear shape, which is option (v).Based on this, the matches are:\(\begin{aligned}&1 \rightarrow \text{(ii)},\&2 \rightarrow \text{(iv)},\&3 \rightarrow \text{(v)}.\end{aligned}\)

Step 3: Find the Correct Option

Review the options provided to find the one that matches:- Option (a) corresponds to: \(1 \rightarrow \text{(ii)}, 2 \rightarrow \text{(iv)}, 3 \rightarrow \text{(v)}.\) The correct option is option (a) because it matches the identified geometry for each type of hybridization.

Key Concepts

Hybridization

Hybridization is a fascinating concept in chemistry that simplifies the understanding of molecular shapes by explaining how atomic orbitals mix to form new, hybrid orbitals. When atoms form bonds, their original atomic orbitals combine in specific ways. This process creates hybrid orbitals, which are better suited for bonding than their original forms. Each type of hybridization corresponds to a specific arrangement of these hybrid orbitals in space.
- **sp hybridization** involves the mixing of one s orbital and one p orbital, producing two equivalent sp orbitals that are 180 degrees apart, resulting in a linear geometry. - **sp² hybridization** involves one s and two p orbitals combining to form three equal sp² hybrid orbitals at 120 degrees to each other, creating a planar trigonal shape. - **sp³ hybridization** consists of one s orbital and three p orbitals mixing to produce four equivalent sp³ hybrid orbitals arranged in a tetrahedron at angles of 109.5 degrees. In hybridization, the type and number of orbitals involved determine the overall shape of the molecule, influencing its chemical properties and reactivity.

Molecular Geometry

Molecular geometry refers to the three-dimensional arrangement of atoms in a molecule. Understanding the shape of a molecule is crucial because it affects how a molecule interacts and reacts with other substances. The geometry is determined by the hybridization of the central atom. For instance:

• With **sp hybridization**, the molecule has a linear shape due to the two regions of electron density arranging themselves as far apart as possible.
• **sp² hybridization** results in a planar trigonal shape because the three areas of electron density spread out in a plane 120 degrees apart.
• **sp³ hybridization** leads to a tetrahedral geometry where four electron cloud regions spread out equally in three dimensions, forming bond angles of 109.5 degrees.

The molecular geometry influences physical and chemical properties such as polarity, phase of matter, color, magnetism, and biological activity. Understanding these shapes helps predict how molecules might interact with one another or with external factors.

Atomic Orbitals

Atomic orbitals are regions surrounding the nucleus of an atom where there is a high probability of finding electrons. Electrons occupy these orbitals in different shapes and sizes, which are defined by quantum numbers. These orbitals are where electron clouds are most dense.
Each element's electron configurations can be understood in terms of these atomic orbitals: - **s orbitals** are spherical and can hold up to two electrons. - **p orbitals** are dumbbell-shaped, possessing three orientations in space which can hold a total of six electrons. - **d and f orbitals** involve more complex shapes and hold a larger number of electrons, relevant in more complex elements. Atomic orbitals form the basis for bonding, as they are the available seats for electrons in bonding and hybridization processes. Knowing the type and shape of these orbitals helps in understanding not only how atoms bond, but also the stability and energy levels of the resulting molecules. These concepts are foundational for predicting molecular behavior in chemical reactions.