Question

Discuss the shape of the following molecules using the VSEPR model:

BeCl₂, BCl₃, SiCl₄, AsF₅, H₂S, PH₃

Answer 1

BeCl_2:

The central atom has no lone pair and there are two bond pairs. i.e., BeCl₂ is of the type AB₂. Hence, it has a linear shape.

BCl_3:

The central atom has no lone pair and there are three bond pairs. Hence, it is of the type AB₃. Hence, it is trigonal planar.

SiCl_4:

The central atom has no lone pair and there are four bond pairs. Hence, the shape of SiCl₄ is tetrahedral being the AB₄ type molecule.

AsF_5:

The central atom has no lone pair and there are five bond pairs. Hence, AsF5 is of the type AB5. Therefore, the shape is trigonal bipyramidal.

H₂S:

The central atom has one lone pair and there are two bond pairs. Hence, H₂S is of the type AB₂E. The shape is Bent.

PH₃:

The central atom has one lone pair and there are three bond pairs. Hence, PH₃ is of the AB₃E type. Therefore, the shape is trigonal pyramidal.