Chem Exam 7,8,9 (molecular shapes)
What counts as one electron domain on a central atom?
- a lone pair of electrons -single bond -a double bond -a triple bond
single bond type; 1 sigma bond; ____ Pi bonds
0
Double bond type; 1 sigma bond; ___ Pi bond
1
what are the steps to predict molecular geometries:
1. draw the lewis structure 2. determine the EDG by aranging the ED about the central atom 3. use arrangement of bonded atoms to determine the MG
for a molecule consisting of more than two atoms the diapole moment depends on both ___
1. the polarities of the individual bonds 2. the geometry of the molecule
bond order formula
1/2 (bonding electrons- antibonding electrons)
Triple bind type; 1 sigma bond; ___ Pi bonds
2
NH3 has _____ electron domains around N. why?
4 (because lone pairs & all bonds count)
if one or more electron domains involve nonbinding electrons, the molecular geometry is
NOT identical to the EDG
one lone pair on central atom makes molecules
POLAR
SF4 molecular shape
Seesaw
methane (CH4), ammonia (NH3) and water (H2O have _____ electron domain geometries but slightly different bond angles
TETRAHEDRAL
CCl4 : molecular geometry
Tetrahedral (no lone pairs on central atom)
what is the ED: 5 lobe electron domains with 120,90 bond angles
Trigonal bipyramid
NH3 : MOLECULAR SHAPE AND POLARITY
Trigonal pyramidal ; polar
a diapole moment is
a property of a molecule whose charge distribution can be represented by a center of positive charge and a center or negative charge
Molecular geometry is the arrangement of only the atoms and DOES NOT consider _____
any nonbonding pairs
SO2 : molecular shape & polarity
bent ; polar (because one lone pair on central atom)
for molecules best represented by resonance structures some electrosn are shared by multiple atoms are called
delocalized electrons
The arrangement of electron domains about the central atom of an ABn molecule or ion is called
electron-domain geometry
sigma bonds
head-to head overlap of orbitals resulting in electron density lying on the line joining two atoms
if electron domain and bonding domains arise from bins then the molecular geometry is
identical to the electron domain geometry
nonbonding pairs experience _____ nuclear attraction and take up more space than binding pairs
less
CO2 : molecular geometry
linear
What is the ED: 2 lobe electron domains w/ 180 degree angle
linear
bonding electrons that are shared between two atoms are called
localized electrons
the bond diaple is represented by an arrow tip pointing toward the _____
more electronegative atom; with the tail pointing to the less negative
The VSEPR model: electron domains are _________ charged and therefore repel each other
negatively
electron-domain geometry (EDG) considers ____
non-bonding & bonding e-
CO2 has two polar bonds w/ a zero overall diapole moment therefore the molecule is
nonpolar
what is the ED: 6 lobe electron domains w/ 90 degree bond angles
octahedral
spatial arrangement of polar bonds determines _____
overall polarity of a molecule
is H2O polar or nonpolar
polar
SF4: molecular shape and polarity
seesaw; polar
Pi bonds
side-to-side overlap of orbitals resulting in electrondensity above and below the line joining two atoms.
linear (2 ED's): hybridzation?
sp
trigonal planar (3 ED's): hybridzation?
sp2
tetrahedral (4 ED's): hyrbridzation?
sp3
trigonal bipyramidal (5 ED's): hybridzation?
sp3d
octahedral (6 ED's) : hybridzation?
sp3d2
XE4 has a ______ molecular geometry 6 ED; 4 bonding domains; 2 non bonding;
square planar
BrF5 has a ____ molecular geometry 6 ED; 5 bonding domains; 1 nonbonding;
square pyramidal
IF5 : molecular shape and polarity
square pyramidal ; polar
what is the ED: 4 lobe electron domains w/ 109.5 bond angles
tetrahedral
if only one bond then polarity of the molecule is ____
the same as polarity of the bond
Molecular geometry of PCl5
trigonal bipyramidal
SO3 : molecular geometry
trigonal planar
What is the ED: 3 lobe electron domains w/ 120 bond angles
trigonal planar
polar covalent bonds result from the
unequal sharing of electrons between two nonmetal atoms (electronegativity differences)
how are covalent bonds formed?
when atomic orbitals on neighboring atoms overlap