What is the molecular geometry of a molecule with 2 outer atoms and 1 lone pair on the central atom?

• A. Tetrahedral
• B. Bent
• C. Trigonal planar
• D. Linear

Answer: (B)

Verified step by step guidance

1. Identify the total number of electron groups around the central atom. In this case, there are 2 outer atoms bonded to the central atom and 1 lone pair, making a total of 3 electron groups.
2. Determine the electron group geometry based on the total number of electron groups. For 3 electron groups, the electron geometry is trigonal planar.
3. Consider the effect of lone pairs on molecular geometry. Lone pairs occupy more space than bonding pairs and cause bond angles to adjust, changing the shape from the ideal electron geometry.
4. Since there are 2 bonded atoms and 1 lone pair, the molecular geometry is not trigonal planar but bent (or angular), because the lone pair pushes the bonded atoms closer together.
5. Conclude that the molecular geometry for a molecule with 2 bonded atoms and 1 lone pair on the central atom is bent, even though the electron geometry is trigonal planar.