Chapter 7, Problem 7.113MP

Interpretation Introduction

(a)

Interpretation:

The electron dot structure of ${\text{Cr}}_{\text{2}}{\text{O}}_{\text{7}}{}^{\text{2-}}$ ion with minimum formal charges on the atoms needs to be determined.

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 bond formation between the atoms takes place due to the sharing of valence electrons of bonded atoms while the remaining electrons present in outer shell represented as lone pair of electrons. To draw the Lewis structure, calculate the total number of valence electrons in each atom and draw the structure in such a way that each atom gets its octet configuration.

Formal charge on each atom can be determined with the help of number of valence shell electrons, number of lone pair electrons and bond pair electrons. The formula for the formal charge can be written as:

$\begin{array}{l}\text{FC = VE – LE – bond pair}\\ \text{FC}\text{}\text{= formal charge}\\ \text{VE = Valence electrons }\\ \text{LE}\text{}\text{= number of lone pair electrons }\\ \text{Bond pair = Number of bond pairs}\end{array}$

Interpretation Introduction

(b)

Interpretation:

The number of outer-shell electrons in each Cr atom in the electron dot structure needs to be determined.

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 bond formation between the atoms takes place due to the sharing of valence electrons of bonded atoms while the remaining electrons present in outer shell represented as lone pair of electrons. To draw the Lewis structure, calculate the total number of valence electrons in each atom and draw the structure in such a way that each atom gets its octet configuration.

Formal charge on each atom can be determined with the help of number of valence shell electrons, number of lone pair electrons and bond pair electrons. The formula for the formal charge can be written as:

$\begin{array}{l}\text{FC = VE – LE – bond pair}\\ \text{FC}\text{}\text{= formal charge}\\ \text{VE = Valence electrons }\\ \text{LE}\text{}\text{= number of lone pair electrons }\\ \text{Bond pair = Number of bond pairs}\end{array}$