What is the molecular geometry of Br3+Br3+ ? bent T-shaped trigonal pyramidal tetrahedral linear
The correct answer and explanation is:
The correct molecular geometry of Br3+\text{Br}_3^+ is T-shaped.
Explanation:
- Valence Shell Electron Pair Repulsion (VSEPR) Theory: VSEPR theory helps predict molecular geometry by considering electron pair repulsion. The central bromine atom in Br3+\text{Br}_3^+ is surrounded by bonding and lone pairs of electrons.
- Electron Configuration: Bromine has 7 valence electrons. For Br3+\text{Br}_3^+, the positive charge indicates one fewer electron, so we account for 20 valence electrons in total for the Br3+\text{Br}_3^+ ion:
- 7 electrons from each bromine atom (×3) = 21
- Remove 1 electron for the positive charge = 20 total valence electrons.
- Lewis Structure: The central bromine atom forms bonds with two terminal bromine atoms. These two bonds account for 4 electrons, leaving 16 electrons as lone pairs. Distribute these around the atoms to satisfy the octet rule:
- Each terminal bromine gets 3 lone pairs (12 electrons total).
- The central bromine gets 2 lone pairs (4 electrons).
- Electron Geometry: The central bromine has 5 regions of electron density (2 bonding pairs and 3 lone pairs). This corresponds to a trigonal bipyramidal electron geometry.
- Molecular Geometry: Of the 5 regions of electron density, the 3 lone pairs occupy the equatorial positions to minimize repulsion. The 2 bonding pairs occupy axial positions, forming a T-shaped molecular geometry.
- Conclusion: The Br3+\text{Br}_3^+ ion adopts a T-shaped geometry due to the arrangement of bonding and lone pairs around the central bromine. This geometry minimizes electron repulsion while accommodating the lone pairs in the most stable configuration.