What is the electronic geometry?
Choose one:
A octahedral
B linear
C tetrahedral
D trigonal planar
E trigonal bypyramidal
The correct answer and explanation is :
The correct answer depends on the number of electron groups around the central atom. Electronic geometry considers both bonding and nonbonding electron pairs to determine the spatial arrangement of electron domains around the central atom.
Correct Answer: It Depends on Electron Domains
Each electronic geometry corresponds to a specific number of electron groups:
- Linear (B) → 2 electron groups
- Trigonal Planar (D) → 3 electron groups
- Tetrahedral (C) → 4 electron groups
- Trigonal Bipyramidal (E) → 5 electron groups
- Octahedral (A) → 6 electron groups
Explanation
Electronic geometry is determined by Valence Shell Electron Pair Repulsion (VSEPR) theory, which states that electron pairs arrange themselves to minimize repulsion. It is different from molecular geometry, which considers only the positions of atoms.
- Linear (B) – 2 Electron Groups
- Example: CO₂ (carbon dioxide)
- Bond Angle: 180°
- Two regions of electron density spread out in a straight line.
- Trigonal Planar (D) – 3 Electron Groups
- Example: BF₃ (boron trifluoride)
- Bond Angle: 120°
- Three electron groups arrange in a flat triangular shape.
- Tetrahedral (C) – 4 Electron Groups
- Example: CH₄ (methane)
- Bond Angle: 109.5°
- Four regions of electron density arrange in a 3D shape.
- Trigonal Bipyramidal (E) – 5 Electron Groups
- Example: PCl₅ (phosphorus pentachloride)
- Bond Angles: 90° & 120°
- Five regions create a shape with two axial and three equatorial positions.
- Octahedral (A) – 6 Electron Groups
- Example: SF₆ (sulfur hexafluoride)
- Bond Angle: 90°
- Six electron groups create an octahedral shape.
Thus, the correct answer depends on the number of electron groups in the molecule.