Chapter 8, Problem 86A

Interpretation Introduction

Interpretation: The electron dot stricture of P, S, and I atoms in ${\text{PCl}}_{\text{5}}$ , ${\text{SF}}_{\text{6}}$ and ${\text{IF}}_{\text{7}}$ needs to be drawn. Also, the hybridization of the central atom, P, S, and I in these compounds needs to be identified.

Concept Introduction: An electron dot structure represents the arrangement of total valence electrons in a molecule. Here, electrons are represented as dots in pairs around the symbol of atoms of the molecule.

VSEPR theory is used to predict the molecular shape with the help of electron pairs around the central atoms of the molecule. It is based on the assumption that the shape of the molecule is such that there is minimum electronic repulsion between the valence shell and the atom.

Explanation of Solution

In ${\text{PCl}}_{\text{5}}$, P is the central atom. Here, 5 chlorine atoms are bonded via single covalent bonds. The valence electrons in P and Cl atoms are 5 and 7 respectively. The arrangement of electrons around atoms takes place in such a way that there are 5 bond pairs of electrons. The electron dot structure can be represented as follows:

  

For the central atom, the sum of bonding electron pairs and non-bonding electron pairs is 5 thus, the hybridization of the central atom will be $s{p}^{3}d$ .

In ${\text{SF}}_{\text{6}}$, S is the central atom. Here, 6 fluorine atoms are bonded to sulfur atoms via single covalent bonds. The valence electrons in S and F atoms are 6 and 7 respectively. The arrangement of electrons around atoms takes place in such a way that there are 6 bond pairs of electrons. The electron dot structure can be represented as follows:

  

For the central atom, the sum of bonding electron pairs and non-bonding electron pairs is 6; thus, the hybridization of the central atom will be $s{p}^3{d}^2$ .

In ${\text{IF}}_{\text{7}}$, I is the central atom. Here, 7 fluorine atoms are bonded to the iodine atom via single covalent bonds. The valence electrons in both I and F atoms are 7. The electron dot structure is represented as follows:

  

For the central atom, the sum of bonding electron pairs and non-bonding electron pairs is 7; thus, the hybridization of the central atom will be $s{p}^3{d}^3$ .