Final answer:
VB sketches focus on bond formation through atomic orbital overlap, while VSEPR sketches show the 3D geometry of molecules based on minimizing electron-pair repulsions. VSEPR theory is used to predict molecular shape by considering the valence electron pairs around the central atom.
Step-by-step explanation:
The difference between a VB (Valence Bond Theory) sketch and a VSEPR (Valence Shell Electron Pair Repulsion) sketch lies in the representation of molecular structure. VB theory focuses on the formation of covalent bonds through the overlap of atomic orbitals, where bond formation is visualized as the sharing of electron pairs between atoms.
On the other hand, VSEPR theory predicts the 3D molecular geometry of a molecule based on electron-pair repulsions. VSEPR sketches depict the spatial arrangement of atom nuclei and pairs of electrons both bonded and lone, to minimize repulsion and determine the shape of the molecule.
VSEPR theory takes into account the number of bonding and lone pairs in the valence shell of the central atom to predict the geometry.
However, VSEPR theory does not give information about bond lengths or the presence of multiple bonds. In contrast, VB theory could explain bond lengths and multiple bond formation but doesn't necessarily predict the overall shape of the molecule.