Shapes and Polarity of M\olecules

University:
California State University, Northridge
Course:
CHEM 101 | General Chemistry I
Academic year:

2023
Views:

410

Pages:

1
Author:

Abbey R.

SHAPES AND POLARITY OF MOLECULES Shapes: Valence-Shell Electron Pair Repulsion Theory (VSEPR) 1. Electron pairs around a central atom repel each other and move apart as far as possible. 2. Atoms assume a geometry dependent upon the electron pair geometry. Polarity 1. Bond dipoles point toward the more electronegative atom of the bond. 2. Bond dipoles are "added" up to determine the overall molecule dipole. (a) If the bond dipoles cancel, the molecule is nonpolar. (b) If bond dipoles do not cancel, the molecule is polar. Number of Electron pair e- pairs around geometry the central atom Number of identical atoms around the central atom Polar Molecule? Atom geometry Examples ?? linear 2 A or bond dipole ?? CO2 2 linear 2 bent NO O C O (bond dipoles cancel) A 3 planar triangular SO2 YES (bond dipoles add) S A O O or A 3 NO SO3 planar triangular (bond dipoles cancel) O S O 4 tetrahedral 2 O H 2O bent YES (bond dipoles add) O A H H or A 3 YES NH3 pyramidal (bond dipoles add) N H H H 4 NO CCl 4 tetrahedral (bond dipoles cancel) Cl C Cl Cl Cl