Chapter U2, Problem C7.2RE

(a)

Interpretation Introduction

Interpretation :

Shape of ammonia molecule must be predicted.

Concept Introduction :

Shape of a molecule is determined by the total number of electron pairs in the valence shell of the central atom.

Ammonia molecule has total 4 atoms in which N is the central atom.

Answer to Problem C7.2RE

Shape of ammonia molecule is trigonal pyramidal.

Explanation of Solution

The structure of ammonia molecule is represented as follows:

N has total 4 pairs of electrons in the valence shell.

There are three bond pairs and lone pairs of electrons. N atom is sp³ hybridized and thus NH₃ has trigonal pyramidal shape due to presence of one lone pair electrons.

b)

Interpretation Introduction

Interpretation :

Shape of silicon tetrachloride must be predicted.

Concept Introduction :

Shape of a molecule is determined by the total number of electron pairs in the valence shell of the central atom.

Silicon tetrachloride molecule has total 5 atoms in which Si is the central atom.

Answer to Problem C7.2RE

Shape of silicon tetrachloride molecule is tetrahedral.

Explanation of Solution

The structure is represented as follows:

Si has total 4 pairs of electrons in the valence shell.

There are four bond pairs and no lone pairs of electrons. Si atom is sp³ hybridized and thus SiCl₄ has tetrahedral shape.

c)

Interpretation Introduction

Interpretation :

Shape of hydrogen sulfide must be predicted.

Concept Introduction :

Shape of a molecule is determined by the total number of electron pairs in the valence shell of the central atom.

Hydrogen sulfide molecule has total 3 atoms in which S is the central atom.

Answer to Problem C7.2RE

Shape of hydrogen molecule is angular.

Explanation of Solution

The structure of H₂S is represented as follows:

S has total 4 pairs of electrons in the valence shell.

There are two bond pairs and two lone pairs of electrons. S atom is sp³ hybridized and thus H₂S has angular shape.

d)

Interpretation Introduction

Interpretation :

Shape of hydrogen cyanide must be predicted.

Concept Introduction :

Shape of a molecule is determined by the total number of electron pairs in the valence shell of the central atom.

Hydrogen cyanide molecule has total 3 atoms in which C is the central atom.

Answer to Problem C7.2RE

Shape of hydrogen cyanide is linear.

Explanation of Solution

The structure is represented as follows:

C has total 4 pairs of electrons in the valence shell.

There are four bond pairs and no lone pairs of electrons. C atom is triple bonded with N and carbon is sp hybridized and thus HCN has linear shape.

e)

Interpretation Introduction

Interpretation :

Shape of formaldehyde must be predicted.

Concept Introduction :

Shape of a molecule is determined by the total number of electron pairs in the valence shell of the central atom.

Formaldehyde molecule has total 4 atoms in which C is the central atom.

Answer to Problem C7.2RE

Shape of formaldehyde is trigonal planar.

Explanation of Solution

The structure of formaldehyde is represented as follows:

C has total 4 pairs of electrons in the valence shell.

There are four bond pairs and no lone pairs of electrons. C atom is double bonded with O and single bonded with two hydrogen atoms. Carbon is sp² hybridized and thus CH₂N has trigonal planar shape.