Bonding Theories

electron domains

areas of electron density

VSEPR

valence shell electron pair repulsion

electron domain geometry

arrangement of electrons around central atom

steric number (SN)

number of electron domains around an atom

linear electron domain geometry

SN = 2

trigonal planar electron domain geometry

SN = 3

tetrahedral electron domain geometry

SN = 4

molecular shape

arrangement of atoms in a molecule

linear, AX₂, 180°

2 BD, 0 LP

trigonal planar, AX₃, 120°

3 BD, 0 LP

tetrahedral, AX₄, 109.5°

4 BD, 0 LP

bent/angular, AX₂E, <120°

2 BD, 1 LP

trigonal pyramidal, AX₃E, <109.5°

3 BD, 1 LP

bent/angular, AX₂E_2, <109.5°

2 BD, 2 LP

wedge-dash notation

3D representation of the structures of molecules

solid line

in plane

wedge

toward you

dash

away from you

polar bond

bond between 2 atoms of different electronegativities

X-X

non-polar bond

X-Y

polar bond

C-H

non-polar bond

polar molecule

molecule where bond dipoles don’t cancel out

net dipole

direction of overall charge separation in a molecule