Chapter 9, Problem 9.105QP

Draw Lewis structures for the following organic molecules: (a) methanol (CH₃OH); (b) ethanol (CH₃CH₂OH); (c) tetraethyllead [Pb(CH₂CH₃)₄], which was used in “leaded gasoline”; (d) methylamine (CH₃NH₂), which is used in tanning; (e) mustard gas (ClCH₂CH₂SCH₂CH₂Cl), a poisonous gas used in World War I; (f) urea [(NH₂)₂CO], a fertilizer; and (g) glycine (NH₂CH₂COOH), an amino acid.

Interpretation Introduction

Interpretation:

Lewis structure of $C{H}_{3}OH$ has to be drawn.

Concept Introduction:

Electron dot structure also known as Lewis dot structure represents the number of valence electrons of an atom or constituent atoms bonded in a molecule.  Each dot corresponds to one electron.

Explanation of Solution

Total valence electrons in $C{H}_{3}OH$ is,

$\left({\text{valence e}}^{\text{-}}\text{ on C }\right)\text{+ }\left({\text{valence e}}^{\text{-}}\text{ on H}\right)\text{+}\left({\text{valence e}}^{\text{-}}\text{ on O}\right)\text{ = 4+4}\left(1\right)\text{+6 = 14}$

Accordingly Lewis structure of $C{H}_{3}OH$ is drawn which shows $14$ electrons in the molecule including bonding and non-bonding electrons.

Interpretation Introduction

Interpretation:

Lewis structure of $C{H}_{3}C{H}_{2}OH$ has to be drawn.

Concept Introduction:

Electron dot structure also known as Lewis dot structure represents the number of valence electrons of an atom or constituent atoms bonded in a molecule.  Each dot corresponds to one electron.

Explanation of Solution

Total valence electrons in $C{H}_{3}C{H}_{2}OH$ is,

$\left({\text{valence e}}^{\text{-}}\text{ on C }\right)\text{+ }\left({\text{valence e}}^{\text{-}}\text{ on H}\right)\text{+}\left({\text{valence e}}^{\text{-}}\text{ on O}\right)\text{ = 2}\left(\text{4}\right)\text{+6}\left(1\right)\text{+6 = 20}$

Accordingly Lewis structure of $C{H}_{3}C{H}_{2}OH$ is drawn which shows $20$ electrons in the molecule, including bonding and non-bonding electrons.

Interpretation Introduction

Interpretation:

Lewis structure of tetraethyllead has to be drawn.

Concept Introduction:

Electron dot structure also known as Lewis dot structure represents the number of valence electrons of an atom or constituent atoms bonded in a molecule.  Each dot corresponds to one electron.

Explanation of Solution

Tetraethyllead is four ethyl groups bonded to lead atom.

Structure of ethyl group is,

Tetraethyllead has molecular formula $Pb{\left(C_2{H}_5\right)}_4$

Total valence electrons in Tetraethyllead is,

$\left(valence{e}^{-}on\text{Pb}\right)+\text{8}\left({\text{valence e}}^{-}on\text{C}\right)+\text{20}\left({\text{valence e}}^{-}on\text{H}\right)=4+8(4)+20=\text{56}$

Accordingly structure of $Pb{\left(C_2{H}_5\right)}_4$ is drawn which shows $56$ electrons in the molecule, including bonding and non-bonding electrons.

In the above structure $C_2{H}_5$ corresponds to,

For simplicity the above structure is written as $C_2{H}_5$

Interpretation Introduction

Interpretation:

Lewis structure of $C{H}_{3}N{H}_2$ has to be drawn.

Concept Introduction:

Electron dot structure also known as Lewis dot structure represents the number of valence electrons of an atom or constituent atoms bonded in a molecule.  Each dot corresponds to one electron.

Explanation of Solution

Total valence electrons in $C{H}_{3}N{H}_2$ is,

$\left(valence{e}^{-}on\text{C}\right)+\text{5}\left({\text{valence e}}^{-}on\text{H}\right)+\left(valence{e}^{-}on\text{N}\right)=4+5\left(1\right)+5=\text{14}$

Accordingly Lewis structure of $C{H}_{3}N{H}_2$ is drawn which shows $14$ electrons in the molecule, including bonding and non-bonding electrons.

Interpretation Introduction

Interpretation:

Lewis structure of mustard gas $ClC{H}_{2}C{H}_{2}SC{H}_{2}C{H}_{2}Cl$ has to be drawn.

Concept Introduction:

Electron dot structure also known as Lewis dot structure represents the number of valence electrons of an atom or constituent atoms bonded in a molecule.  Each dot corresponds to one electron.

Explanation of Solution

Total valence electrons in $ClC{H}_{2}C{H}_{2}SC{H}_{2}C{H}_{2}Cl$ is,

$\begin{array}{l}4\left(valence{e}^{-}on\text{C}\right)+\left(valence{e}^{-}on\text{S}\right)+2\left(valence{e}^{-}on\text{Cl}\right)+\\ \text{8}\left(valence{e}^{-}on\text{H}\right)=\text{4}\left(4\right)+6+2\left(7\right)+8\left(1\right)\\ =\text{16+6+14+8}\text{=}\text{44}\end{array}$

Accordingly Lewis structure of $ClC{H}_{2}C{H}_{2}SC{H}_{2}C{H}_{2}Cl$ is drawn which shows $44$ electrons in the molecule, including bonding and non-bonding electrons.

Interpretation Introduction

Interpretation:

Lewis structure of urea ${\left(N{H}_2\right)}_{2}CO$ has to be drawn.

Concept Introduction:

Electron dot structure also known as Lewis dot structure represents the number of valence electrons of an atom or constituent atoms bonded in a molecule.  Each dot corresponds to one electron.

Explanation of Solution

Total valence electrons in ${\left(N{H}_2\right)}_{2}CO$ is,

$\begin{array}{l}\left(valence{e}^{-}on\text{C}\right)+4\left({\text{valence e}}^{-}on\text{H}\right)+\text{2}\left({\text{valence e}}^{-}on\text{N}\right)\\ +\left(valence{e}^{-}on\text{O}\right)=4+4\left(1\right)+2\left(5\right)+\text{6 }\\ =\text{4+4+10+6 = 24}\end{array}$

Accordingly Lewis structure of ${\left(N{H}_2\right)}_{2}CO$ is drawn which shows $24$ electrons in the molecule, including bonding and non-bonding electrons.

Interpretation Introduction

Interpretation:

Lewis structure of glycine ($N{H}_{2}C{H}_{2}COOH$) has to be drawn.

Concept Introduction:

Electron dot structure also known as Lewis dot structure represents the number of valence electrons of an atom or constituent atoms bonded in a molecule.  Each dot corresponds to one electron.

Explanation of Solution

Total valence electrons in $N{H}_{2}C{H}_{2}COOH$ is,

$\begin{array}{l}2\left(valence{e}^{-}on\text{C}\right)+5\left({\text{valence e}}^{-}on\text{H}\right)+\left({\text{valence e}}^{-}on\text{N}\right)\\ +\text{2}\left(valence{e}^{-}on\text{O}\right)=\text{2}\left(4\right)+5\left(1\right)+5+\text{2}\left(6\right)\\ =\text{8+5+5+12 = 30}\end{array}$

Accordingly Lewis structure of $N{H}_{2}C{H}_{2}COOH$ is drawn which shows $30$ electrons in the molecule, including bonding and non-bonding electrons.