VSEPR theory includes two types of geometries: electron geometry and molecular geometry. What is the difference between the two geometries?
A. The electron geometry only considers lone pairs of electrons and the molecular geometry only considers the atoms.
B. There is no difference between electron and molecular geometries; they are simply different names for the same thing.
C. Electron geometry describes the arrangement of the electron groups in a molecule, whereas the molecular geometry describes the arrangement of the atoms.
D. Lone pairs are included in the electron geometry but play no role in the molecular geometry.
question
PF3, SBr2, CH3Br
answer
In which cases do you expect deviations from the idealized bond angle? (Check all that apply)
PF3
SBr2
CH3Br
BCl3
Since PF3 and SBr2 both have lone pairs of electrons on the central atom, their bond angles should deviate from the idealized bond angle as lone pairs are more repulsive than bonding pairs of electrons. Large atoms, such as Cl or Br, will cause bond angles to deviate from the ideal, and the presence of a multiple bond will cause a deviation as well owing to the increased electron density, so CH3Br should deviate from the idealized bond angle. BCl3 has identical atoms symmetrically surrounding a central atom with no lone pairs on it, so BCl3 should not deviate from the idealized bond angle.
