What kind of geometry does H2S have?
The correct answer and explanation is:
Correct Answer: The geometry of H₂S is bent (or V-shaped).
Explanation:
Hydrogen sulfide (H₂S) is a molecule composed of two hydrogen atoms and one sulfur atom. To determine its geometry, start with its Lewis structure. Sulfur is the central atom with six valence electrons. Each hydrogen contributes one valence electron. The total number of valence electrons is eight. Two electrons form a single bond with each hydrogen, using four electrons. The remaining four electrons stay as two lone pairs on sulfur.
The molecular geometry of a compound depends on the number of bonding pairs and lone pairs around the central atom. In H₂S, sulfur has two bonding pairs and two lone pairs. According to the Valence Shell Electron Pair Repulsion (VSEPR) theory, electron pairs around a central atom arrange themselves to minimize repulsion.
With four electron regions (two bonds and two lone pairs), the ideal electron-pair geometry would be tetrahedral. However, lone pairs exert greater repulsive force than bonding pairs, so they push the bonding pairs closer together. This distortion changes the observed molecular shape from tetrahedral to bent.
In H₂O, which is similar to H₂S, the bond angle is about 104.5°. In H₂S, the bond angle is slightly smaller, about 92°, because sulfur is larger and less electronegative than oxygen, so the lone pair repulsions are weaker, and bonding pairs are pushed even closer.
The bent shape of H₂S also means it has a dipole moment and is a polar molecule. The difference in electronegativity between hydrogen and sulfur contributes to the polarity, although it is not as strong as in water.
In conclusion, the geometry of H₂S is bent, resulting from two bonding pairs and two lone pairs on the sulfur atom, as predicted by VSEPR theory.