In which of the following molecules can you confidently predict the bond angles about the central atom, and for which would you be a bit uncertain? Explain in each case. (a) H2S, (b) BCl3, (c) CH3I, (d) CBr4, (e) TeBr4.

Key Concepts

VSEPR Theory

Valence Shell Electron Pair Repulsion (VSEPR) Theory is a model used to predict the geometry of individual molecules based on the repulsion between electron pairs in the valence shell of the central atom. According to this theory, electron pairs will arrange themselves as far apart as possible to minimize repulsion, which helps in determining bond angles and molecular shapes.

Hybridization

Hybridization is the concept of mixing atomic orbitals to form new hybrid orbitals that can accommodate the bonding pairs of electrons. The type of hybridization (e.g., sp, sp2, sp3) influences the geometry and bond angles of a molecule, as it determines how many orbitals are involved in bonding and their spatial arrangement.

Lone Pairs and Bond Angles

Lone pairs of electrons can affect bond angles in a molecule because they occupy space and exert repulsive forces on bonding pairs. This can lead to deviations from ideal bond angles predicted by VSEPR Theory. Understanding the presence and influence of lone pairs is crucial for accurately predicting molecular geometry and bond angles.