Chapter 6, Problem 44QRT

Interpretation Introduction

Interpretation:

The correct Lewis structure of Peroxydisulfate ion ${\text{(S}}_{\text{2}}{\text{O}}_8^{2-}\text{)}$ and ${\text{SO}}_{\text{4}}^{\text{2-}}$ ion with formal charge of each atom have to be written.

Concept Introduction:

Lewis structure otherwise known as Lewis dot diagrams or electron dot structures. The bond between atoms and lone pairs of electrons that is present in the molecule.  Lewis structure represents each atom and their position in structure using the chemical symbol.  Excess electrons forms the lone pair are given by pair of dots, and are located next to the atom.

The formula for the formal charge can be written as

  $\text{Formal}\text{charge=}\text{Valence}\text{electrons-lone}\text{pair}\text{electrons}\text{-}\frac{\text{Bonding}\text{electrons}}{\text{2}}$

Explanation of Solution

The correct Lewis structure of Peroxydisulfate ion ${\text{(S}}_{\text{2}}{\text{O}}_8^{2-}\text{)}$ can be drawn as,

Achart can be drawn as,

  $\overline{\begin{array}{l}S\text{O(of}\text{S=O)}\text{O(of}\text{S-O)}\text{O(of}O\text{-O)}\\ \overline{\underset{\_}{\begin{array}{l}\text{Valence}\text{electrons}66\text{6}6\\ \text{Lone}\text{pair}\text{electrons}04\text{6}4\\ \text{Bonding}\text{electrons}124\text{2}\text{4}\\ \text{Formal}\text{charge}00-10\end{array}}}\end{array}}$

Lewis structures with formal charges to each atom.

${\text{(S}}_{\text{2}}{\text{O}}_8^{2-}\text{)}$ molecule has $60$ valence electron and the central Oxygen-Oxygen bond to two multiple bond.

The ${\text{SO}}_{\text{4}}^{\text{2-}}$ molecule has $32$ electrons total.  The correct Lewis structure for this ion ends up as shown below

        

$\overline{\begin{array}{l}S\text{O(of}\text{S=O)}\text{O(of}\text{S-O)}\\ \overline{\underset{\_}{\begin{array}{l}\text{Valence}\text{electrons}66\text{6}\\ \text{Lone}\text{pair}\text{electrons}04\text{6}\\ \text{Bonding}\text{electrons}124\text{2}\\ \text{Formal}\text{charge}00-1\end{array}}}\end{array}}$

Lewis structures with formal charges to each atom.