Draw Lewis structures for the following species in the boxes provided and use them to answer the questions below: What is the electron pair geometry for SiS_(2) ? a. linear b. trigonal planar c. tetrahedral d. trigonal bipyramidal e. octahedral What is the molecular shape of SiS_(2) ? a. tetrahedral b. bent c. trigonal pyramidal d. linear e. trigonal planar The approximate S-Si-S bond angle(s) in SiS_(2) is/are: a. 90deg b. 109.5deg c. 120deg d. 90deg and 120deg e. 180deg What is the electron pair geometry for PCl_(5) ? a. linear b. trigonal planar c. tetrahedral d. trigonal bipyramidal e. octahedral What is the molecular shape of PCl_(5) ? a. trigonal bipyramidal b. bent c. tetrahedral d. T-shape e. trigonal planar The approximate Br-P-Br bond angle(s) in PCl_(5) is/are: a. 90deg b. 109.5deg c. 120deg d. 90deg and 120 e. 180deg The SiS_(2) molecule is and the PCl_(5) molecule is b. polar, polar b. nonpolar, polar c. polar, nonpolar d. nonpolar, nonpolar Draw Lewis structures for the following species in the boxes provided and use them to answer the questions below SiS2 PBrs What is the electron pair geometry for SiS? a. linear d. trigonal bipyramidal b. trigonal planar e.octahedral c.tetrahedral What is the molecular shape of SiS? a.tetrahedral d. linear b.bent e.trigonal planar c. trigonal pyramidal The approximate S-Si-S bond angle(s) in SiSis/are a.90 b. 109.5 c.120 d. 90 and 120 e. 180 What is the electron pair geometry for PCIs? a. linear d.trigonal bipyramidal b. trigonal planar e.octahedral c. tetrahedral What is the molecular shape of PCls? a. trigonal bipyramidal d.T-shape b. bent e. trigonal planar c. tetrahedral The approximate Br-P-Br bond angle(s) in PCls is/are: a. 90 b.109.5 c.120 d.90 and 120 e. 180 The SiS molecule is and the PCls molecule is b. polar, polar c. polar, nonpolar b. nonpolar, polar d. nonpolar, nonpolar
The Correct Answer and Explanation is:
Correct Answers:
For SiS₂:
- Electron pair geometry: a. linear
- Molecular shape: d. linear
- S–Si–S bond angle(s): e. 180°
For PCl₅:
- Electron pair geometry: d. trigonal bipyramidal
- Molecular shape: a. trigonal bipyramidal
- Cl–P–Cl bond angle(s): d. 90° and 120°
Polarity:
- The SiS₂ molecule is d. nonpolar,
- The PCl₅ molecule is d. nonpolar
Explanation:
1. SiS₂ (Silicon disulfide):
In the Lewis structure of SiS₂, the central silicon atom is bonded to two sulfur atoms with double bonds. Silicon has four valence electrons and each sulfur has six. Each sulfur shares two electrons with silicon to form a double bond, completing the octet for all atoms. There are no lone pairs on the central silicon atom. Since there are only two bonding regions and no lone pairs, the electron pair geometry is linear. This results in a linear molecular shape with a bond angle of 180 degrees. The molecule is nonpolar because the two polar bonds are arranged symmetrically, and their dipoles cancel out.
2. PCl₅ (Phosphorus pentachloride):
In PCl₅, phosphorus has five valence electrons and forms five single bonds with five chlorine atoms. There are no lone pairs on phosphorus. The electron pair geometry is trigonal bipyramidal, consisting of three atoms in the equatorial plane at 120 degrees and two atoms in the axial positions at 90 degrees to the equator. This gives a trigonal bipyramidal molecular shape. Because of the symmetry in this shape and the fact that all surrounding atoms are identical, PCl₅ is a nonpolar molecule, even though the P–Cl bonds are individually polar. The symmetry causes the dipoles to cancel each other out.
In conclusion, SiS₂ and PCl₅ are both nonpolar molecules with linear and trigonal bipyramidal geometries, respectively.
