Vsepr Theory And Shape Of Molecules

Step 1: Understanding the Thermal Decomposition of Ammonium Nitrate
The thermal decomposition reaction of ammonium nitrate ( ) is: The colourless neutral gas formed in this reaction is Nitrous Oxide ( ).
Step 2: Determining the Molecular Shape of
- The molecular structure of (Nitrous Oxide) is: - The molecule consists of sp hybridized nitrogen atoms.
- It follows the linear geometry due to no lone pairs affecting the molecular shape.
Step 3: Conclusion Since has a linear molecular shape, the correct answer is: which matches Option (2).

Step 1: Finding Lone Pairs on the Central Atom
Lone pairs on the central atom can be determined using the VSEPR (Valence Shell Electron Pair Repulsion) theory.
1. Bromine Pentafluoride ( )
- Bromine ( ) has 7 valence electrons.
- It forms 5 single bonds with fluorine atoms.
- Total valence electrons used in bonding: .
- Remaining electrons: (1 lone pair).
- Molecular geometry: Square pyramidal.
2. Xenon Trioxide ( )
- Xenon ( ) has 8 valence electrons.
- It forms 3 double bonds with oxygen atoms.
- Total valence electrons used in bonding: .
- Remaining electrons: (1 lone pair).
- Molecular geometry: Trigonal pyramidal.
3. Sulfur Trioxide ( )
- Sulfur ( ) has 6 valence electrons.
- It forms 3 double bonds with oxygen atoms.
- Total valence electrons used in bonding: .
- Remaining electrons: (No lone pairs).
- Molecular geometry: Trigonal planar.
Step 2: Conclusion The number of lone pairs on the central atom for each molecule: Thus, the correct answer is , which matches option (4).