Chapter 8.3, Problem 48PP

Interpretation Introduction

Interpretation:

The Lewis resonance structure for ${\text{PCl}}_{\text{5}}$ needs to be explained.

Concept introduction:

Lewis structure is also known as electron − dot structure which is showing the bonding between atoms of a molecule and used for atoms to show their valence electron.

Answer to Problem 48PP

Lewis structure is a representation of the valence electrons of an atom that uses dot around the symbol of the element, where number of dots around of the element and number of dots equal to the number of valence electrons in the atom.

Atomic number of phosphorous $15=2,8,5$

Valence electrons $=5$

Atomic number of Chlorine $17=2,8,7$

Valence electrons $=7$

Total valence electrons $=5+5\times 7=40$

Or

Explanation of Solution

P is less electronegative than Cl. Thus phosphorous (P) becomes the central atom and $5$ chlorine (Cl) will be the terminal atoms. Then assign single bonds between the central atoms and the terminal atoms. Then assign the remaining un − paired electrons for each atom accoding to their number of valence electrons.

$\begin{array}{l}\text{atom Number of atoms valence electron}\\ \text{ electrons configuration}\\ \text{P 1 5 }\left[\text{Ne}\right]{\text{ 3s}}^2{\text{ 3p}}^3\\ \text{Cl 3 7 }\left[\text{Ne}\right]{\text{ 3s}}^2{\text{ 3p}}^5\end{array}$

Conclusion

Molecular geometry of ${\text{PCl}}_{\text{5}}$ is trigonal bipyramid (there are no lone pair interaction). Chlorine (Cl) is more electronegative than phosphorous (P). Thus, the bonds are polar but overall ${\text{PCl}}_{\text{5}}$ is non − polar because of arrangement of chlorine (Cl) atoms.