Chapter U2.10, Problem 5E

Interpretation Introduction

Interpretation:

Three molecules having a tetrahedral shape needs to be listed.

Concept Introduction:

Pure tetrahedral shape involves sp³ hybridization (One s orbital & 3 p orbitals) with the angle of 109.5°.

Explanation of Solution

If the central atom in a molecule has sp³ hybridization then the shape of the molecule is tetrahedral.

In a tetrahedral molecule, central atom has 4 bond pairs and zero lone pair.

The three molecules having tetrahedral shape are methane, ammonium ion and phosphate ion. The methane molecule the structure of the molecule is represented as follows:

  

Here, C atom is bonded to 4 H atoms thus, the hybridization is sp³.

The ammonium ion is represented as follows:

  

In ammonium ion ${\text{NH}}_4^{+}$ , N has 5 valence electrons. It can form maximum of 3 bonds. Thus, to form bond with 1 more H atom N atom can use its lone pair of electron.

Thus, in ${\text{NH}}_4^{+}$ there will be 4 bonding pair of electrons and zero lone pair with 1 positive charge. The shape of the molecule will be tetrahedral.

The structure of phosphate ion is represented as follows:

  

Here, number of valence electrons in P is 5 which are used up in the formation of 1 double bond and 3 single bonds with O.

Thus, in phosphate ion there are 4 bonding pair of electrons and zero lone pair of electrons. The shape will be tetrahedral.