Problem 43 - 43 Years JEE ADVANCED (1978-2020) + JEE MAIN Chapterwise & Topicwise Solved Papers Chemistry

Question

On hybridization of one \(s\) and one \(p\) orbitals we get : (a) two mutually perpendicular orbitals (b) two orbitals at \(180^{\circ}\) (c) four orbitals directed tetrahedrally (d) three orbitals in a plane

Step-by-Step Solution

Answer

(b) Two orbitals at 180°.

Step 1: Understand the Concept of Hybridization

Hybridization in chemistry is the concept of mixing atomic orbitals to form new hybrid orbitals suitable for the pairing of electrons. In this exercise, we are mixing one \(s\) orbital and one \(p\) orbital.

Step 2: Identify the Type of Hybridization

When one \(s\) orbital mixes with one \(p\) orbital, it forms an \(sp\) hybridization. This results in two equivalent orbitals.

Step 3: Determine the Orbital Geometry

In an \(sp\) hybridization, the geometry of the orbitals formed is linear. The orbitals are oriented at \(180^\circ\) to each other.

Step 4: Select the Correct Answer

From the options provided, (b) is correct, as \(sp\) hybridization results in two orbitals at \(180^{\circ}\).

Key Concepts

Atomic Orbitals

To understand hybridization, it's crucial to start with atomic orbitals. Atomic orbitals are regions around an atom's nucleus where electrons are likely to be found. They have different shapes and energy levels, defining how electrons occupy space around an atom. The most common types are:

• s orbital: Spherically shaped and found in every energy level.
• p orbital: Dumbbell-shaped, with three orientations in space (px, py, pz), starting from the second energy level.
• d orbital: More complex, found from the third energy level onwards, with five orientations.
• f orbital: Even more complex, available from the fourth energy level with seven orientations.

Each orbital can hold a maximum of two electrons with opposite spins. Understanding the properties of atomic orbitals is essential, as they form the building blocks for hybridization.

sp Hybridization

When discussing the mixing of atomic orbitals, the term "hybridization" often comes up. Specifically, sp hybridization is a process where one s orbital combines with one p orbital. This fusion results in two identical and equivalent sp hybrid orbitals.

These hybrid orbitals are crucial because:

• They offer a model to explain molecular bond formation.
• They alter the energy and orientation of electron regions, leading to new geometries.

In sp hybridization, the two sp orbitals are equivalent, but distinct from the original s and p orbitals. The combination of these orbitals usually happens in molecules like acetylene (C₂H₂), where linear geometry is necessary. Therefore, each hybrid orbital has 50% s character and 50% p character, which impacts the molecule's chemical properties.

Orbital Geometry

The configuration of hybrid orbitals in space is known as orbital geometry. In the case of sp hybridization, the resulting geometry is linear. This means the two sp orbitals are arranged around the atom in a straight line.

Why does this happen?

• The combination of one s and one p orbital results in two orbitals that aim to be as far apart as possible to minimize repulsion.
• The linear arrangement allows the orbitals to be placed at an angle of 180° relative to each other.

This linear geometry is key for molecules needing such spatial arrangements, like carbon monoxide (CO) and acetylene (C₂H₂).

Understanding orbital geometry helps predict the shape and angle between bonds, ultimately affecting molecular properties and reactions.