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., $BeCl_2$ is of the type $AB_2$. 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 $AB_3$. Hence, it is trigonal planar.
$SiCl_4$:

The central atom has no lone pair and there are four bond pairs. Hence, the shape of $SiCl_4$ is tetrahedral being the $AB_4$ type molecule.
$AsF_5$:

The central atom has no lone pair and there are five bond pairs. Hence, $AsF_5$ is of the type $AB_5$. Therefore, the shape istrigonal bipyramidal.
$H_2S$:

The central atom has one lone pair and there are two bond pairs. Hence, $H_2S$ is of the type $AB_2E$. The shape is Bent.
$PH_3$:

The central atom has one lone pair and there are three bond pairs. Hence, $PH_3$ is of the $AB_3E$ type. Therefore, the shape is trigonal pyramidal.