Final answer:
The hybridization of the central atom beryllium in beryllium chloride is sp hybridization, leading to a linear molecular geometry with two σ bonds formed with chlorine atoms.
Step-by-step explanation:
The hybridization of the central atom in beryllium chloride, which is beryllium (Be), is sp hybridization. The beryllium atom in gaseous BeCl₂ has two regions of valence electron density, corresponding to the two covalent Be-Cl bonds without any lone pairs of electrons.
To account for these two electron domains, the beryllium atom's valence s orbital mixes with one of its p orbitals to produce two equivalent sp hybrid orbitals. These are oriented linearly, 180° apart. The hybrid orbitals overlap with the chlorine atoms' orbitals to form two σ bonds, resulting in a linear molecular geometry. Since there are only two regions, the hybridization is sp and not sp², sp³, or sp³d².