Question

Discuss the shape of the following molecules using the `VSEPR` model:
`BeCl_(2)`,`BCl_(3)`,`SiCl_(4)`,`AsF_(5)`,`H_(2)S`,`PH_(3)`

Answer 1

`BeCl_(2)`
`Cl:Be:Cl`
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)`
`Cl: overset(Cl) overset(..) B: Cl`
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)`
`Cl:underset(Cl)underset(..)overset(Cl)overset(..)Si:Cl`
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 is trigonal bipyramidal.
`H_(2)S`
`H: overset(..)S:H`
The central atom has one pair and there are two bond pairs. Hence, `H_(2)S` is of the type `AB_(2)E`. The shape is Bent.
`PH_(3)`:
`H: underset(H)underset(..)overset(..)P:H`
The central atom has one lone pair and there are three bond pairs. Hence, `PH_(3)` is of the `AB_(3)E` type. Therefore, the shape is trigonal bipyramidal.