VSEPR theory? Seesaw B. T-shaped Bent or V-shaped D, Trigonal planar Tetrahedral
Question 2 What is the molecular geometry of IBr3 according to the VSEPR theory? Seesaw B. T-shaped Bent or V-shaped D, Trigonal planar Tetrahedra
The Correct Answer and Explanation is:
The correct answer is: B. T-shaped
Explanation:
To determine the molecular geometry of IBr₃ using VSEPR (Valence Shell Electron Pair Repulsion) theory, follow these steps:
Step 1: Determine the number of valence electrons
- Iodine (I) is in group 17, so it has 7 valence electrons.
- Each bromine (Br) also has 7 valence electrons, and there are 3 Br atoms.
However, for geometry, we focus on the central atom—Iodine.
Step 2: Bonding and lone pairs on iodine
- Iodine forms three single bonds with each Br atom, using 3 of its 7 valence electrons.
- This leaves 4 electrons, or 2 lone pairs (since each lone pair consists of 2 electrons).
So iodine in IBr₃ has:
- 3 bonding pairs (Br atoms),
- 2 lone pairs.
This results in a total of 5 regions of electron density.
Step 3: Use VSEPR to predict shape
With 5 electron regions, the electron geometry is trigonal bipyramidal. However, lone pairs occupy equatorial positions to minimize repulsion.
- The 3 Br atoms occupy two axial and one equatorial position.
- The 2 lone pairs occupy the remaining equatorial positions.
Step 4: Determine the molecular geometry
When a molecule has:
- 3 bonding pairs,
- 2 lone pairs,
- in a trigonal bipyramidal electron geometry,
The molecular geometry is T-shaped.
Conclusion:
The lone pairs distort the ideal shape, and the three bonded atoms form a T-shaped structure. Hence, according to VSEPR theory, the molecular geometry of IBr₃ is T-shaped.
✅ Correct answer: B. T-shaped
