What do you understand by Hybridization? Explain different types of hybridizations involving s and p orbitals.

Hybridization refers to the process of intermixing atomic orbitals of an atom with nearly equal energies to form an equal number of new, identical orbitals. These newly formed orbitals are called hybrid orbitals, and they have specific geometries and properties.

Types of Hybridization Involving s and p Orbitals

1. sp3 Hybridization

sp³ hybridization involves the mixing of one s orbital and three p orbitals, resulting in four identical sp3 hybrid orbitals. Each of these hybrid orbitals has 25% s-character and 75% p-character. The bond angles between the sp3 hybrid orbitals are approximately 109°28', and the molecules adopting this hybridization typically have a tetrahedral shape.

Example: Methane (CH₄) molecule

In methane, the carbon atom undergoes sp3 hybridization in its excited state. The four hybrid orbitals overlap with the 1s orbitals of four hydrogen atoms to form a tetrahedral molecule with a bond angle of 109°28'.

2. sp2 Hybridization

sp² hybridization occurs when one s orbital and two p orbitals mix to form three sp2 hybrid orbitals. These orbitals have 33.33% s-character and 66.67% p-character. The bond angles between the sp2 hybrid orbitals are 120°, resulting in a planar triangular shape.

Example: Boron Trichloride (BCl₃) molecule

In boron trichloride, the boron atom undergoes sp2 hybridization in its excited state. Three sp2 hybrid orbitals overlap with the half-filled 3p orbitals of chlorine atoms to form a planar triangular molecule with bond angles of 120°.

3. sp Hybridization

sp hybridization involves the intermixing of one s orbital and one p orbital to form two identical sp hybrid orbitals. Each hybrid orbital has 50% s-character and 50% p-character. The bond angle between the sp hybrid orbitals is 180°, and molecules adopting this hybridization have a linear shape.

Example: Beryllium Chloride (BeCl₂) molecule

In beryllium chloride, the beryllium atom undergoes sp hybridization in its excited state. The two sp hybrid orbitals overlap with the 3p orbitals of chlorine atoms to form a linear molecule with a bond angle of 180°.

Conclusion

Hybridization is a key concept in chemistry that explains the shapes and geometries of molecules. By understanding different types of hybridization such as sp3, sp2, and sp, we can predict the bond angles, molecular shapes, and other chemical properties of compounds.