Question

Se the VSEPR theory to predict the shape of each of the following molecules:

Which molecules are Trigonal Planar?
a) Ammonia (NH₃)
b) Silane (SiH₄)
c) Hydrogen Selenide (H₂Se)
d) Carbon Tetraiodide (CI₄)

Answer 1

None of the listed molecules (Ammonia (NH₃), Silane (SiH₄), Hydrogen Selenide (H₂Se), Carbon Tetraiodide (CI₄)) are Trigonal Planar. Using VSEPR theory, Ammonia is trigonal pyramidal, Silane and Carbon Tetraiodide are tetrahedral, and Hydrogen Selenide is bent.

Step-by-step explanation:

The student is asking to use VSEPR theory to predict the shape of various molecules and identify which of them are Trigonal Planar.

VSEPR (Valence Shell Electron Pair Repulsion) theory is used for predicting the shapes of molecules based on the number of electron pairs surrounding their central atoms.

• Ammonia (NH₃): Ammonia has one lone pair and three bonded pairs of electrons around the nitrogen atom, giving it a trigonal pyramidal shape, not trigonal planar.
• Silane (SiH₄): Silane has four bonded pairs of electrons around the silicon atom and no lone pairs, resulting in a tetrahedral shape, not trigonal planar.
• Hydrogen Selenide (H₂Se): Hydrogen selenide has two bonded pairs and two lone pairs of electrons around the selenium atom, which results in a bent or v-shaped molecular geometry, again not trigonal planar.
• Carbon Tetraiodide (CI₄): Carbon tetraiodide has four bonded pairs and no lone pairs around the carbon atom, so it also has a tetrahedral shape, not trigonal planar.

Based on the given options, none of the listed molecules have a trigonal planar shape.