Problem 31 - Chemistry: The Central Science

Question

Using Lewis symbols and Lewis structures, diagram the formation of \(\mathrm{SiCl}_{4}\) from \(\mathrm{Si}\) and \(\mathrm{Cl}\) atoms.

Step-by-Step Solution

Answer

The Lewis symbols for Si and Cl are: Si has 4 valence electrons and Cl has 7 valence electrons, represented as dots around the chemical symbols. The Lewis structure for SiCl4 is formed by silicon sharing its valence electrons with each of the four chlorine atoms, forming single covalent bonds and satisfying the octet rule for both atoms. The Lewis structure for SiCl4 is: \(\hspace{11mm} \mathrm{Cl} \) \(\hspace{7.5mm} // \backslash\) \(\mathrm{Cl} - \mathrm{Si} - \mathrm{Cl}\) \(\hspace{7.5mm} // \backslash\) \(\hspace{11mm} \mathrm{Cl} \)

Step 1: Determine the Lewis symbols for Si and Cl

Begin by identifying the valence electrons of silicon (Si) and chlorine (Cl). Silicon has 4 valence electrons and is located in group 14, while chlorine has 7 valence electrons and is located in group 17. Represent these valence electrons as dots around the chemical symbols. The Lewis symbols for Si and Cl are: Si: \(\cdot \hspace{1mm} \mathrm{Si} \hspace{1mm} \cdot\) \: \: \: \: \: \: \: \: \: \: \: \|/ Cl: \(\cdot \hspace{0.5mm} \mathrm{Cl} :\)

Step 2: Combine the atoms to form SiCl4

Now, silicon will form covalent bonds by sharing its valence electrons with each of the four chlorine atoms to satisfy the octet rule for both atoms. To illustrate this bonding, show the electron sharing between the atoms and represent the bonded electrons as lines. The Lewis structure for SiCl4 is: \(\hspace{11mm} \mathrm{Cl} \) \(\hspace{7.5mm} // \backslash\) \(\mathrm{Cl} - \mathrm{Si} - \mathrm{Cl}\) \(\hspace{7.5mm} // \backslash\) \(\hspace{11mm} \mathrm{Cl} \) In this Lewis structure, the silicon atom shares a pair of electrons with each of the four chlorine atoms, forming single covalent bonds. Each chlorine atom has now satisfied the octet rule, having four bonded electrons and three lone pair electrons. The silicon atom also satisfies the octet rule by sharing its four valence electrons with the chlorine atoms.