Chapter 13, Problem 109E

(a)

Interpretation Introduction

Interpretation: The Lewis structure and the molecular structure with polarity of molecule needs to be determined.

  ${\text{OCl}}_{\text{2}}{\text{, KrF}}_{\text{2}}{\text{, BeH}}_{\text{2}}{\text{, SO}}_{\text{2}}$

Concept Introduction:

Lewis dot structure is the representation which shows the bonding between atoms present in a molecule. It shows lone pairs and bond pairs that exist on each bonded atom. Lewis dot structure is also known as Lewis dot formula or electron dot structure.

The hybridization and molecular structure of molecule determine the molecular structure of molecule.

  $\text{Hybridization = Number of sigma bonds + Number of lone pairs on bonded atoms}\text{.}$

For a molecule to be polar, it should have polar bond with no symmetry in the molecule.

Answer to Problem 109E

  ${\text{OCl}}_{\text{2}}$ is a polar molecule as it has two O-F polar bonds with bent geometry.

  ${\text{KrF}}_{\text{2}}$ is a non-polar molecule as it has two Kr-F polar bonds are arranged in linear geometry.

  ${\text{BeH}}_{\text{2}}$ is a non-polar molecule as it has linear geometry.

  ${\text{SO}}_{\text{2}}$ is a polar molecule as it has two O-S polar bonds with bent geometry.

Explanation of Solution

In ${\text{OCl}}_{\text{2}}$ molecule, the total number of valence electrons; $(1\times 6)+(2\times 7)=20$

Hence the best Lewis structure for ${\text{OCl}}_{\text{2}}$ must be:

  

  $\begin{array}{l}\text{Hybridization = Number of sigma bonds + Number of lone pairs on bonded atoms}\text{.}\\ \text{Hybridization = 2 + 2 = 4 = sp}\text{= bent }\end{array}$

It is a polar molecule as it has two O-F polar bonds with bent geometry.

In ${\text{KrF}}_{\text{2}}$ molecule, the total number of valence electrons; $(1\times 8)+(2\times 7)=22$

Hence the best Lewis structure for ${\text{KrF}}_{\text{2}}$ must be:

  

  $\begin{array}{l}\text{Hybridization = Number of sigma bonds + Number of lone pairs on bonded atoms}\text{.}\\ \text{Hybridization = 2 + 3 = 5 = sp}\text{d}\text{ = linear}\end{array}$

  ${\text{KrF}}_{\text{2}}$ is a non-polar molecule as it has two Kr-F polar bonds are arranged in linear geometry.

In ${\text{BeH}}_{\text{2}}$ molecule, the total number of valence electrons; $(1\times 2)+(2\times 1)=4$

Hence the best Lewis structure for ${\text{BeH}}_{\text{2}}$ must be:

  

  $\begin{array}{l}\text{Hybridization = Number of sigma bonds + Number of lone pairs on bonded atoms}\text{.}\\ \text{Hybridization = 2 + 0 = 2 = sp = linear}\end{array}$

  ${\text{BeH}}_{\text{2}}$ is a non-polar molecule as it has linear geometry.

In ${\text{SO}}_{\text{2}}$ molecule, the total number of valence electrons; $(1\times 6)+(2\times 6)=18$

Hence the best Lewis structure for ${\text{SO}}_{\text{2}}$ must be:

  

  $\begin{array}{l}\text{Hybridization = Number of sigma bonds + Number of lone pairs on bonded atoms}\text{.}\\ \text{Hybridization = 2 + 1 = 3 = sp}\text{= bent }\end{array}$

  ${\text{SO}}_{\text{2}}$ is a polar molecule as it has two O-S polar bonds with bent geometry.

(c)

Interpretation Introduction

Interpretation: The Lewis structure and the molecular structure with polarity of molecule needs to be determined.

  ${\text{CF}}_{\text{4}}{\text{, SeF}}_4{\text{, KrF}}_4$

Concept Introduction:

Lewis dot structure is the representation which shows the bonding between atoms present in a molecule. It shows lone pairs and bond pairs that exist on each bonded atom. Lewis dot structure is also known as Lewis dot formula or electron dot structure.

The hybridization and molecular structure of molecule determine the molecular structure of molecule.

  $\text{Hybridization = Number of sigma bonds + Number of lone pairs on bonded atoms}\text{.}$

For a molecule to be polar, it should have polar bond with no symmetry in the molecule.

Answer to Problem 109E

  ${\text{CF}}_{\text{4}}$ is a non-polar molecule as it has 4 C-F polar bonds with tetrahedral geometry.

  ${\text{KrF}}_4$ has square planer structure therefore it is non-polar.

  ${\text{BeH}}_{\text{2}}$ is a non-polar molecule as it has linear geometry.

  ${\text{SO}}_{\text{2}}$ is a polar molecule as it has two O-S polar bonds with bent geometry.

Explanation of Solution

In ${\text{CF}}_{\text{4}}$ molecule, the total number of valence electrons; $(1\times 4)+(4\times 7)=32$

Hence the best Lewis structure for ${\text{CF}}_{\text{4}}$ must be:

  

  $\begin{array}{l}\text{Hybridization = Number of sigma bonds + Number of lone pairs on bonded atoms}\text{.}\\ \text{Hybridization = 2 + 2 = 4 = sp}\text{= tetrahedral}\end{array}$

  ${\text{CF}}_{\text{4}}$ is a non-polar molecule as it has 4 C-F polar bonds with tetrahedral geometry.

In ${\text{KrF}}_4$ molecule, the total number of valence electrons; $(1\times 8)+(4\times 7)=36$

Hence the best Lewis structure for ${\text{KrF}}_4$ must be:

  

  $\begin{array}{l}\text{Hybridization = Number of sigma bonds + Number of lone pairs on bonded atoms}\text{.}\\ \text{Hybridization = 4 + 2 = 6= sp}\text{d}{}^{\text{2}}\text{ = square planer}\end{array}$

  ${\text{KrF}}_4$ hassquare planer structure therefore it is non-polar.

In ${\text{SeF}}_4$ molecule, the total number of valence electrons; $(1\times 6)+(4\times 7)=34$

Hence the best Lewis structure for ${\text{SeF}}_4$ must be:

  

  $\begin{array}{l}\text{Hybridization = Number of sigma bonds + Number of lone pairs on bonded atoms}\text{.}\\ {\text{Hybridization = 4 + 1 = 5= sp}}^{\text{3}}\text{d = see-saw}\end{array}$

  ${\text{SeF}}_4$ is a non-polar molecule as it has see-saw geometry.

(d)

Interpretation Introduction

Interpretation: The Lewis structure and the molecular structure with polarity of molecule needs to be determined.

  ${\text{IF}}_{\text{5}}{\text{,AsF}}_{\text{5}}$

Concept Introduction:

Lewis dot structure is the representation which shows the bonding between atoms present in a molecule. It shows lone pairs and bond pairs that exist on each bonded atom. Lewis dot structure is also known as Lewis dot formula or electron dot structure.

The hybridization and molecular structure of molecule determine the molecular structure of molecule.

  $\text{Hybridization = Number of sigma bonds + Number of lone pairs on bonded atoms}\text{.}$

For a molecule to be polar, it should have polar bond with no symmetry in the molecule.

Answer to Problem 109E

  ${\text{ICl}}_{\text{5}}$ is a polar molecule due to square pyramid geometry.

  ${\text{AsF}}_{\text{5}}$ is a non-polar molecule due to trigonal bipyramid geometry.

Explanation of Solution

According to the given molecular formula, the structure of ${\text{ICl}}_{\text{5}}$ must be:

  $(1\times 7)+(5\times 7)=42$

Hence the best Lewis structure for ${\text{ICl}}_{\text{5}}$ must be:

  

  $\begin{array}{l}\text{Hybridization = Number of sigma bonds + Number of lone pairs on bonded atoms}\text{.}\\ \text{Hybridization = 5 + 1 = 6 = sp}\text{d}{}^{\text{2}}\text{ = square pyramid}\end{array}$

  ${\text{ICl}}_{\text{5}}$ is a polar molecule due to square pyramid geometry.

According to the given molecular formula, the structure of ${\text{AsF}}_{\text{5}}$ must be:

  $(1\times 5)+(5\times 7)=40$

Hence the best Lewis structure for ${\text{AsF}}_{\text{5}}$ must be:

  

  $\begin{array}{l}\text{Hybridization = Number of sigma bonds + Number of lone pairs on bonded atoms}\text{.}\\ {\text{Hybridization = 5 +0 = 5 = sp}}^{\text{3}}\text{d = trigonal bipyramidal}\end{array}$

  ${\text{AsF}}_{\text{5}}$ is a non-polar molecule due to trigonal bipyramidgeometry.