Question

Using the VSEPR theory, predict the molecular structure of each of the following molecules. a. \(\mathrm{Cl}_{2} \mathrm{O}\) b. \(\mathrm{OF}_{2}\) c. \(\mathrm{SiCl}_{4}\)

Short answer

The molecular structures of the given molecules are as follows: a. \(\mathrm{Cl}_{2} \mathrm{O}\): Bent with a bond angle of approximately 104.5° between the O-Cl bonds. b. \(\mathrm{OF}_{2}\): Bent with a bond angle of approximately 104.5° between the O-F bonds. c. \(\mathrm{SiCl}_{4}\): Tetrahedral with bond angles of approximately 109.5° between the Si-Cl bonds.

Step-by-step solution

a. Predicting the molecular structure of \(\mathrm{Cl}_{2} \mathrm{O}\)

Step 1: Identify the central atom. In \(\mathrm{Cl}_{2} \mathrm{O}\), the central atom is the oxygen (O) atom, which is bonded to two chlorine (Cl) atoms. Step 2: Calculate the total number of valence electrons. Oxygen has 6 valence electrons, and each chlorine atom has 7 valence electrons. The total number of valence electrons in \(\mathrm{Cl}_{2} \mathrm{O}\) is 6 + 7(2) = 20. Step 3: Determine the number of bonding and nonbonding electron pairs. The oxygen atom is bonded to two chlorine atoms, forming two bonding pairs in the molecule. The oxygen atom also has two nonbonding electron pairs. Step 4: Predict the molecular structure based on VSEPR theory. According to VSEPR theory, the oxygen atom will arrange its two lone pairs and bonding pairs as far away from each other as possible. This results in a bent molecular structure with a bond angle of approximately 104.5° between the O-Cl bonds.

b. Predicting the molecular structure of \(\mathrm{OF}_{2}\)

Step 1: Identify the central atom. In \(\mathrm{OF}_{2}\), the central atom is the oxygen (O) atom, which is bonded to two fluorine (F) atoms. Step 2: Calculate the total number of valence electrons. Oxygen has 6 valence electrons, and each fluorine atom has 7 valence electrons. The total number of valence electrons in \(\mathrm{OF}_{2}\) is 6 + 7(2) = 20. Step 3: Determine the number of bonding and nonbonding electron pairs. The oxygen atom is bonded to two fluorine atoms, forming two bonding pairs in the molecule. The oxygen atom also has two nonbonding electron pairs. Step 4: Predict the molecular structure based on VSEPR theory. Similar to \(\mathrm{Cl}_{2}\mathrm{O}\), the oxygen atom in \(\mathrm{OF}_{2}\) will arrange its two lone pairs and bonding pairs as far away from each other as possible. This results in a bent molecular structure with a bond angle of approximately 104.5° between the O-F bonds.

c. Predicting the molecular structure of \(\mathrm{SiCl}_{4}\)

Step 1: Identify the central atom. In \(\mathrm{SiCl}_{4}\), the central atom is the silicon (Si) atom, which is bonded to four chlorine (Cl) atoms. Step 2: Calculate the total number of valence electrons. Silicon has 4 valence electrons, and each chlorine atom has 7 valence electrons. The total number of valence electrons in \(\mathrm{SiCl}_{4}\) is 4 + 7(4) = 28. Step 3: Determine the number of bonding and nonbonding electron pairs. Silicon is bonded to four chlorine atoms, forming four bonding pairs in the molecule. Silicon has no nonbonding pairs because all four valence electrons participate in forming bonds with the chlorine atoms. Step 4: Predict the molecular structure based on VSEPR theory. According to VSEPR theory, the four chlorine atoms bonded to the silicon atom will arrange themselves as far away from each other as possible. This results in a tetrahedral molecular structure with bond angles of approximately 109.5° between the Si-Cl bonds.