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