Which of the following molecule is of T – shape? A. I3 B. ClF3 C. SF4 D. XeF4
The correct answer and explanation is:
Correct Answer: B. ClF₃
Explanation (Approx. 300 words):
The molecule that adopts a T-shape molecular geometry is ClF₃ (chlorine trifluoride).
To understand why ClF₃ has a T-shaped geometry, we must apply the principles of VSEPR theory (Valence Shell Electron Pair Repulsion Theory), which is used to predict the shape of molecules based on the repulsion between electron pairs (bonding and nonbonding) around a central atom.
Step-by-step Analysis of ClF₃:
- Central Atom: Chlorine (Cl)
- Valence Electrons in Cl: 7
- Bonds with Fluorine: 3 Cl–F single bonds use 3 bonding pairs of electrons.
- Lone Pairs on Cl: Remaining 4 electrons = 2 lone pairs.
- Total Electron Pairs Around Cl: 3 bonding pairs + 2 lone pairs = 5 electron domains.
According to VSEPR theory, 5 electron domains arrange themselves in a trigonal bipyramidal electron geometry to minimize repulsion. In this geometry:
- The equatorial positions are more spacious than the axial ones.
- Lone pairs prefer equatorial positions to minimize repulsion.
So, in ClF₃:
- The two lone pairs occupy two equatorial positions.
- The three fluorine atoms occupy the two axial positions and one remaining equatorial position.
This results in a T-shaped molecular geometry.
Why the Others Are Not T-Shaped:
- A. I₃⁻: Linear geometry (3 atoms with 2 lone pairs on central atom).
- C. SF₄: See-saw shape (5 electron domains: 4 bonding, 1 lone pair).
- D. XeF₄: Square planar shape (6 electron domains: 4 bonding, 2 lone pairs opposite each other).
Conclusion:
ClF₃ has 5 electron pairs (3 bonding + 2 lone), and the geometry that minimizes repulsion with this configuration is T-shaped. Thus, option B is correct.