VSEPR

Question 1

Type: AB₂

Answer 1

Type: AB₂
Electron Pairs: 2
Bond Pairs: 2
Lone Pairs: 0
Electron Geometry: Linear
Molecular Geometry: Linear
Bond Angle: 180°
Example: BeCl₂

Question 2

Type: AB₃

Answer 2

Type: AB₃
Electron Pairs: 3
Bond Pairs: 3
Lone Pairs: 0
Electron Geometry: Trigonal Planar
Molecular Geometry: Trigonal Planar
Bond Angle: 120°
Example: BF₃

Question 3

Type: AB₂E

Answer 3

Type: AB₂E
Electron Pairs: 3
Bond Pairs: 2
Lone Pairs: 1
Electron Geometry: Trigonal Planar
Molecular Geometry: Bent / V-Shaped
Bond Angle: ~117°
Example: SO₂, SnCl₂

Question 4

Type: AB₄

Answer 4

Type: AB₄
Electron Pairs: 4
Bond Pairs: 4
Lone Pairs: 0
Electron Geometry: Tetrahedral
Molecular Geometry: Tetrahedral
Bond Angle: 109.5°
Example: CH₄

Question 5

Type: AB₃E

Answer 5

Type: AB₃E
Electron Pairs: 4
Bond Pairs: 3
Lone Pairs: 1
Electron Geometry: Tetrahedral
Molecular Geometry: Trigonal Pyramidal
Bond Angle: ~107°
Example: NH₃

Question 6

Type: AB₂E₂

Answer 6

Type: AB₂E₂
Electron Pairs: 4
Bond Pairs: 2
Lone Pairs: 2
Electron Geometry: Tetrahedral
Molecular Geometry: Bent / V-Shaped
Bond Angle: ~104.5°
Example: H₂O

Question 7

Type: AB₅

Answer 7

Type: AB₅
Electron Pairs: 5
Bond Pairs: 5
Lone Pairs: 0
Electron Geometry: Trigonal Bipyramidal
Molecular Geometry: Trigonal Bipyramidal
Bond Angle: 90°, 120°, 180°
Example: PCl₅

Question 8

Type: AB₆

Answer 8

Type: AB₆
Electron Pairs: 6
Bond Pairs: 6
Lone Pairs: 0
Electron Geometry: Octahedral
Molecular Geometry: Octahedral
Bond Angle: 90°, 180°
Example: SF₆

Question 9

Q: What does VSEPR stand for?

Answer 9

Valence Shell Electron Pair Repulsion Theory
It predicts molecular geometry based on repulsions between electron pairs.

Question 10

Q: What are the basic postulates of VSEPR theory?

Answer 10

> Electron pairs around the central atom repel each other.

> Molecules adjust their shape to minimize repulsions.

> Lone pairs take more space than bond pairs.

> Molecular shape depends only on atoms, not lone pairs.

> Double/triple bonds act like a single bond in shape prediction.

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Question 11

Q: What is the order of repulsion strength among electron pairs?

Answer 11

Lone Pair – Lone Pair > Lone Pair – Bond Pair > Bond Pair – Bond Pair
In short:
lp-lp > lp-bp > bp-bp

Question 12

Q: How do lone pairs affect molecular geometry?

Answer 12

Lone pairs push bonding pairs closer, reducing bond angles and changing the shape (e.g., from tetrahedral to bent).
The more lone pairs = the more distortion 🌀

Question 13

Q: Can electron pair geometry and molecular geometry be different?

Answer 13

✅ YES!
When lone pairs are present, the molecular geometry changes even if electron geometry stays the same.
🧠 Example:
=>Electron geometry of NH₃: Tetrahedral
=>Molecular geometry of NH₃: Trigonal Pyramidal

Question 14

Q: How is hybridization related to VSEPR?

Answer 14

> 2 e⁻ pairs → sp (linear)
3 e⁻ pairs → sp² (trigonal planar)
4 e⁻ pairs → sp³ (tetrahedral)
5 e⁻ pairs → sp³d (trigonal bipyramidal)
6 e⁻ pairs → sp³d² (octahedral)