Which of the following is closest to the bond angle in ozone (O_3) as predicted by its Lewis structure?

• A. 90^ext{o}
• B. 117^ext{o}
• C. 120^ext{o}
• D. 104.5^ext{o}

Answer: (B)

Verified step by step guidance

1. Step 1: Draw the Lewis structure of ozone (O_3). Ozone has a total of 18 valence electrons (6 from each oxygen atom). Arrange the atoms with one oxygen in the center and the other two on the sides, then distribute electrons to satisfy the octet rule as much as possible.
2. Step 2: Identify the electron domains around the central oxygen atom. In ozone, the central oxygen is bonded to two other oxygens and has one lone pair of electrons, giving a total of three regions of electron density (two bonding pairs and one lone pair).
3. Step 3: Use the VSEPR (Valence Shell Electron Pair Repulsion) theory to predict the molecular geometry. Three electron domains around the central atom correspond to a trigonal planar electron geometry, but the presence of one lone pair changes the molecular shape to bent or angular.
4. Step 4: Understand that lone pairs repel more strongly than bonding pairs, which compresses the bond angle between the two oxygen atoms bonded to the central oxygen. The ideal trigonal planar angle is 120°, but the lone pair reduces this angle.
5. Step 5: Conclude that the bond angle in ozone is slightly less than 120°, typically around 117°, which matches the answer closest to the predicted bond angle based on the Lewis structure and VSEPR theory.