What is the molecular geometry of the bromate ion, BrO_3^-?

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

Answer: (C)

Verified step by step guidance

1. Determine the Lewis structure of the bromate ion (BrO_3^-). Start by counting the total number of valence electrons: bromine (Br) has 7 valence electrons, each oxygen (O) has 6, and add 1 extra electron for the negative charge.
2. Draw the skeletal structure with bromine as the central atom bonded to three oxygen atoms. Distribute the electrons to satisfy the octet rule for each atom, placing lone pairs as needed.
3. Count the number of bonding pairs and lone pairs around the central bromine atom. This will help determine the electron pair geometry using the VSEPR (Valence Shell Electron Pair Repulsion) theory.
4. Apply VSEPR theory: the molecular geometry depends on the number of bonding pairs and lone pairs on the central atom. For example, if there are three bonding pairs and one lone pair, the shape is trigonal pyramidal.
5. Conclude the molecular geometry of BrO_3^- based on the arrangement of atoms and lone pairs around bromine, which leads to the trigonal pyramidal shape.