(a) What is hybridization? (b) What are the conditions for an atom to undergo hybridization? (c) How can we explain the shapes and bond angles of \(\mathrm{BeCl}_{2}, \mathrm{BCl}_{3}\) and \(\mathrm{CH}_{4}\) with hybridization?

Hybridization is a phenomenon in which atomic orbitals of similar energies (usually valence orbitals) on the central atom of a molecule combine or mix to form new orbitals called hybrid orbitals. The purpose of hybridization is to achieve more stable molecular structures, as the electrons in these hybrid orbitals are more evenly distributed, resulting in stronger and more stable bonds.

For an atom to undergo hybridization, the following conditions must be met: 1. The atom should have more than one valence orbital (s, p, and d orbitals). 2. The orbitals combining should have similar energies and shapes. 3. The number of hybrid orbitals formed is equal to the number of atomic orbitals that have combined.

To explain the shapes and bond angles using hybridization, we will determine the hybridization state of the central atom in each molecule and then deduce the molecular geometry. 1. BeCl2: - Central atom: Be (Beryllium) - Hybridization: The Be atom contains two valence electrons in the 2s orbital, which can hybridize with the 2p orbital to form two sp hybrid orbitals. - Geometry: The two sp hybrid orbitals will arrange linearly to minimize electron repulsion. - Bond angle: As the hybrid orbitals are arranged linearly, the bond angle between Cl-Be-Cl is 180°. 2. BCl3: - Central atom: B (Boron) - Hybridization: The B atom contains three valence electrons, one in the 2s orbital and two in the 2p orbitals. These can hybridize to form three sp2 hybrid orbitals. - Geometry: The three sp2 hybrid orbitals will arrange in a trigonal planar arrangement to minimize electron repulsion. - Bond angle: In a trigonal planar arrangement, the bond angle between any two Cl-B-Cl bonds is 120°. 3. CH4: - Central atom: C (Carbon) - Hybridization: The C atom contains four valence electrons, two in the 2s orbital and two in the 2p orbitals. These can hybridize to form four sp3 hybrid orbitals. - Geometry: The four sp3 hybrid orbitals will arrange in a tetrahedral arrangement to minimize electron repulsion. - Bond angle: In a tetrahedral arrangement, the bond angle between any two H-C-H bonds is 109.5°.