Which of the following is the bond angle in a molecule of carbon dioxide (CO_2)?

• A. 180^ext{o}
• B. 120^ext{o}
• C. 109.5^ext{o}
• D. 90^ext{o}

Answer: (A)

Verified step by step guidance

1. Identify the molecular geometry of carbon dioxide (CO\_2). CO\_2 has a central carbon atom double bonded to two oxygen atoms, with no lone pairs on the carbon.
2. Determine the electron domain geometry around the central atom. Since there are two regions of electron density (the two double bonds), the electron domain geometry is linear.
3. Recall that a linear molecular geometry corresponds to bond angles of 180\^\{\text{o}\}.
4. Compare this with other common bond angles: 120\^\{\text{o}\} corresponds to trigonal planar, 109.5\^\{\text{o}\} to tetrahedral, and 90\^\{\text{o}\} to octahedral or square planar geometries.
5. Conclude that the bond angle in CO\_2 is 180\^\{\text{o}\} due to its linear shape.