What is the Lewis Structure for NH3Cl+? b. What is the electron domain geometry? c. What is the molecular geometry? d. Is it polar or nonpolar? 2. Is SnCl3- polar or nonpolar?
The Correct Answer and Explanation is:
NH₃Cl⁺ (Ammonium Chloride Cation)
a. Lewis Structure
NH₃Cl⁺ is a positively charged ion derived from ammonia (NH₃) and HCl. The structure is based on ammonium (NH₄⁺) where one H is replaced by a Cl. So, the nitrogen is bonded to three H atoms and one Cl atom, with a +1 overall charge.
- N is the central atom with 5 valence electrons.
- Each H contributes 1 electron.
- Cl contributes 7 electrons.
- There is a total of: 5 (N) + 3 (H) + 7 (Cl) – 1 (charge) = 14 valence electrons
Lewis Structure:
markdownCopyEdit H
|
H - N⁺ - Cl
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H
There are 4 bonds around nitrogen and no lone pairs on N.
b. Electron Domain Geometry
- There are 4 regions of electron density (4 bonding pairs).
- Electron domain geometry: Tetrahedral
c. Molecular Geometry
- Since all 4 electron domains are bonding, the shape is:
- Molecular geometry: Tetrahedral
d. Polarity
- Cl is more electronegative than H, creating an uneven distribution of charge.
- The asymmetry from the N–Cl bond causes a net dipole moment.
- Result: Polar molecule
2. SnCl₃⁻ (Tin Trichloride Anion)
Lewis Structure and Geometry:
- Tin (Sn) is the central atom with 4 valence electrons.
- Each chlorine contributes 7 valence electrons.
- Add 1 extra electron for the negative charge.
- Total: 4 (Sn) + 3×7 (Cl) + 1 = 26 valence electrons
Each Cl forms a single bond with Sn. Sn ends up with 3 bonding pairs and 1 lone pair (total 4 regions of electron density).
- Electron domain geometry: Tetrahedral
- Molecular geometry: Trigonal pyramidal (due to one lone pair)
Polarity:
- The trigonal pyramidal shape creates an asymmetric distribution of electrons.
- Chlorine atoms are highly electronegative, pulling electron density away from Sn.
- This results in a net dipole moment.
✅ Conclusion: SnCl₃⁻ is polar.
Summary
| Species | Electron Geometry | Molecular Geometry | Polar/Nonpolar |
|---|---|---|---|
| NH₃Cl⁺ | Tetrahedral | Tetrahedral | Polar |
| SnCl₃⁻ | Tetrahedral | Trigonal Pyramidal | Polar |
Both species have asymmetrical shapes with polar bonds, leading to overall polarity.
