Write the best lew is structure for PCl3Br2 and explain why. Explain why you positioned the atoms the way that you did and use bond angles to decipher what would be the most staple to minimize bonding pair-bonding pair repulsion.
General credit information is considered obsolete after _ years.
A three (3)
B four (4)
C five (5)
D seven (7)
E eight (8)
The Correct Answer and Explanation is :
Lewis Structure and Molecular Geometry of PCl₃Br₂
Phosphorus trichloride dibromide (PCl₃Br₂) consists of a central phosphorus (P) atom bonded to three chlorine (Cl) atoms and two bromine (Br) atoms. To determine its optimal Lewis structure and molecular geometry, we apply the Valence Shell Electron Pair Repulsion (VSEPR) theory, which posits that electron pairs around a central atom arrange themselves to minimize repulsion, thereby determining the molecule’s shape.
Step 1: Counting Valence Electrons
- Phosphorus (P): 5 valence electrons
- Chlorine (Cl): 7 valence electrons × 3 = 21
- Bromine (Br): 7 valence electrons × 2 = 14
- Total valence electrons: 5 + 21 + 14 = 40
Step 2: Determining Electron Pair Geometry
With five regions of electron density (three P–Cl bonds and two P–Br bonds), the electron pair geometry around the phosphorus atom is trigonal bipyramidal.
Step 3: Assigning Positions to Minimize Repulsion
In a trigonal bipyramidal arrangement, there are two distinct positions: axial and equatorial. Equatorial positions are 120° apart, while axial positions are 90° from equatorial positions. To minimize electron pair repulsion, the more electronegative atoms should occupy positions that reduce repulsive interactions.
Chlorine is slightly more electronegative than bromine. Therefore, placing the three chlorine atoms in the equatorial positions and the two bromine atoms in the axial positions minimizes repulsion. This arrangement ensures that the larger bromine atoms are 180° apart, reducing steric hindrance, and the chlorines are separated by 120°, balancing repulsive forces.
Step 4: Evaluating Bond Angles
- Equatorial (Cl–P–Cl) bond angles: 120°
- Axial (Br–P–Br) bond angle: 180°
- Axial-equatorial (Br–P–Cl) bond angles: 90°
This configuration minimizes bonding pair–bonding pair repulsion, as the 120° and 180° angles reduce interactions between electron pairs compared to 90° angles.
Conclusion
The optimal Lewis structure for PCl₃Br₂ features a central phosphorus atom with three chlorine atoms in equatorial positions and two bromine atoms in axial positions, forming a trigonal bipyramidal geometry. This arrangement minimizes bonding pair–bonding pair repulsion by maximizing bond angles, leading to a more stable molecular structure.
General Credit Information Obsolescence
Credit information is generally considered obsolete after seven years. This time frame is based on regulations that limit how long negative information can remain on a credit report. After seven years, most negative items, such as late payments or defaults, are removed, reflecting an individual’s current creditworthiness more accurately. Therefore, the correct answer is:
D. Seven (7)