SF3 20. BrF5 1. SiO3 2. NH4CIO2 (indicate the electron pair geometry and molecular shape around each ion.) 2- Molecular Lewis DotAXE Type Electron Formula Structure on Central Molecular onic, 2 Shape polar,
The Correct Answer and Explanation is :
To address this question, let’s go through the electron pair geometry and molecular shapes for each molecule or ion (SF3, BrF5, SiO3, NH4ClO2) using the AXE method (A = central atom, X = atoms bonded to A, E = lone pairs on A).
1. SF3 (Sulfur Trifluoride)
- Lewis Structure: Sulfur (S) is the central atom, bonded to three fluorine (F) atoms, with one lone pair of electrons on sulfur.
- Electron Pair Geometry (EPG): Tetrahedral (4 regions of electron density: 3 bonding regions and 1 lone pair)
- Molecular Shape: Trigonal pyramidal (due to the lone pair on sulfur)
- Polarity: The molecule is polar because the fluorine atoms are highly electronegative, creating a dipole.
2. BrF5 (Bromine Pentafluoride)
- Lewis Structure: Bromine (Br) is the central atom, bonded to five fluorine (F) atoms, with one lone pair of electrons on bromine.
- Electron Pair Geometry (EPG): Octahedral (6 regions of electron density: 5 bonding regions and 1 lone pair)
- Molecular Shape: Square pyramidal (due to the lone pair on bromine)
- Polarity: The molecule is polar because of the asymmetry of the fluorine atoms around the central bromine atom.
3. SiO3 (Silicate Ion)
- Lewis Structure: Silicon (Si) is the central atom, bonded to three oxygen (O) atoms, each with a negative charge, forming a trigonal planar structure.
- Electron Pair Geometry (EPG): Trigonal planar (3 regions of electron density: 3 bonding regions)
- Molecular Shape: Trigonal planar
- Polarity: This ion is nonpolar due to the symmetry of the three oxygen atoms surrounding the central silicon atom.
4. NH4ClO2 (Ammonium Chlorite)
- Lewis Structure: Nitrogen (N) is the central atom, bonded to four hydrogen (H) atoms. The chlorite ion (ClO2) is attached to the nitrogen via a coordinate bond.
- Electron Pair Geometry (EPG): Tetrahedral (4 regions of electron density: 4 bonding regions)
- Molecular Shape: Tetrahedral
- Polarity: The ammonium ion (NH4+) is nonpolar due to the symmetrical distribution of the hydrogen atoms.
Summary
- SF3: Tetrahedral EPG, Trigonal Pyramidal Molecular Shape, Polar
- BrF5: Octahedral EPG, Square Pyramidal Molecular Shape, Polar
- SiO3: Trigonal Planar EPG, Trigonal Planar Molecular Shape, Nonpolar
- NH4ClO2: Tetrahedral EPG, Tetrahedral Molecular Shape, Nonpolar
These geometries are based on the VSEPR (Valence Shell Electron Pair Repulsion) theory, which predicts the arrangement of atoms and electron pairs to minimize repulsion.