Chapter 8, Problem 83A

(a)

Interpretation Introduction

Interpretation: The incorrect bonds in the given electron dot structure of ${\text{C}}_{\text{2}}{\text{H}}_{\text{2}}$ needs to be identified and the correct electron dot structure needs to be drawn.

Concept Introduction: An electron dot structure represents the arrangement of total valence electrons in a molecule. Here, electrons are represented as dots in pairs around the symbol of atoms of the molecule.

Explanation of Solution

The given molecule is ${\text{C}}_{\text{2}}{\text{H}}_{\text{2}}$

. The structure given in the question is as follows:

  

Here, C can maximum form 4 bonds and H can maximum of 1 bond. Hydrogen cannot form a double bond with any atom of the element. Thus, it will be C-H single bonds. Now, each carbon must form 4 bonds thus, it will C-C triple bond instead of a double bond. Also, in an electron dot structure, a binding pair of electrons and lone pair of electrons are shown around the atoms. The correct electron dot structure can be represented as follows:

  

(b)

Interpretation Introduction

Interpretation: The incorrect bonds in the given electron dot structure of $\text{FOH}$ needs to be identified and the correct electron dot structure needs to be drawn.

Concept Introduction: An electron dot structure represents the arrangement of total valence electrons in a molecule. Here, electrons are represented as dots in pairs around the symbol of atoms of the molecule.

Explanation of Solution

The given molecule is FOH, the given electron dot structure is as follows:

  

In the above structure, F is singly bonded to an oxygen atom which is then bonded to a hydrogen atom. Here, the octet for F, O, and H is complete but all the lone pairs of electrons are not represented.

Here, F has 7 valence electrons thus, there should be 3 lone pairs of electrons on the F atom. Similarly, the valence electrons of the oxygen atom are 6 and it should have 2 lone pairs of electrons. The correct electron dot structure is as follows:

  

(c)

Interpretation Introduction

Interpretation: The incorrect bonds in the given electron dot structure of $\text{ICl}$ needs to be identified and the correct electron dot structure needs to be drawn.

Concept Introduction: An electron dot structure represents the arrangement of total valence electrons in a molecule. Here, electrons are represented as dots in pairs around the symbol of atoms of the molecule.

Explanation of Solution

The given molecule is ICl, the given electron dot structure is as follows:

  

Here, I and Cl both have 7 valence electrons thus, each needs one electron to complete the octet. Iodine and Chlorine can share one electron each to form a covalent bond. Since one bond pair is shared thus, a single bond is formed between I and Cl. Moreover, there will be 3 lone pairs of electron/s each on I and Cl atoms. The correct electron dot structure can be represented as follows:

  

(d)

Interpretation Introduction

Interpretation: The incorrect bonds in the given electron dot structure of ${\text{N}}_{\text{2}}{\text{H}}_{\text{2}}$ needs to be identified and the correct electron dot structure needs to be drawn.

Concept Introduction: An electron dot structure represents the arrangement of total valence electrons in a molecule. Here, electrons are represented as dots in pairs around the symbol of atoms of the molecule.

Explanation of Solution

The given molecule is ${\text{N}}_{\text{2}}{\text{H}}_{\text{2}}$ and given electron dot structure are as follows:

  

Here, the number of valence electrons in the N and H atoms is 5 and 1 respectively. Here, the octet of N is not completed. H atom can maximum share one electron thus, only a single bond is possible. After the formation of single bonds with N, there will be 4 electrons in each N atom. Thus, it will have an N-N double bond. Also, there will be 1 lone pair of electrons on each N atom.

The correct electron dot structure is represented as follows: