chap 5 Flashcards
define Valence Shell Electron Pair Repulsion Theory(vsepr- vesper)
model to predict electron-pair and molecular geometry based on repulsion of negative charge from electrons about central atom
define electron pair geometry and what pairs it refers to?
the spatial arrangement of all electron pairs excluding lone pairs around a central atom in a molecule
define molecular geometry and pairs it applies to
the spatial arrangement of bonding pairs including lone pairs around a central atom in a molecule
define steric number
packages of negative charge. O=C=O is SN=2
what are the five base geometrys and SN that applies to them
SN=2 linear
SN=3 trigonal planar
SN=4 tetrahedral
SN=5 trigonal bipyramidal
SN=6 octahedral
3d view of base geometry and their angles degrees
linear- 180° straight
trigonal planar- 120° three prong
tetrahedral- 109.5° horizontal 3prong bottom with vertical top
trigonal bipyramidal-90° axial 120° equatorial. 2 vetrical axis 3 horizontal prong
octagedral- 90° 4 prong horizontal 2 vertical axis
electron pair geometry and molecular geometry…
are equal UNLESS HAVE LONE PAIRS
electron pair geometry vs molecular geometry when there’s lone pairs and degrees
SN=3 EPG-trigonal planar 1LP MG- bent <120°
SN=4 EPG-tetrahedral LP MG-trigonal pyramidal <109.5° 2LP MG-bent <109.5°
SN=5 EPG- trigonal bipyramidal 1LP MG-seesaw <90° <120° 2LP MG- T-shaped <90° 3LP MG-linear 180°
SN=6 EPG-octahedral 1LP MG-square pyramidal <90° 2LP MG-square planar 90°
define permenant dipole moment
if lewis molecule has lone pairs the dipoles merge to point to atom with most EN
define polar molecule
same dipole moment not in opposition.
when is bond angle changed?
when lone pair present cause it has more repulsion so pushes away bonds from it
ways to tell if a molecule is polar?
it has hydrogen multi compound or has a lone pair
why will something have a higher boiling pt?
if its polar because it takes more enegry to break a polar bond than a nonpolar
