Chem 115 VSEPR

Shape of molecule/ion is determined by the _______ about the central atom

total number of regions of electron density

Lone pairs and bonding e- pairs each count as ____

regions of e- density

Regions of e- _____ each other and adopt an arrangement so as to be as ______ as possible

repel, far apart

Five basic electron arrangements

AX2, AX3, AX4, AX5, AX6

AX2 has ___ electron domains, and _____ electron pair geometry

2, linear

AX3 has ____ electron domains, and ____ electron pair geometry

3, trigonal planar

AX4 has ___ electron domains, and _____ electron pair geometry

4, tetrahedral

AX5 has ___ electron domains, and _____ electron pair geometry

5, trigonal bipyramidal

AX5 electron pair geometry has _________ positions

equatorial and axial

_____ positions are substituted first

equatorial

e,e bond angles

120

a,e bond angles

90

AX6 has ___ electron domains, and _____ electron pair geometry

6, octahedral

Nonbonding domains exert a ______ electrical field than bonding domains

greater

When they are not the same type, electron domains are ________ distributed

not equally

Molecular geometry

basic shapes are distorted by nonbonding domains

Trigonal planar molecular geometries

AB3, AB2E1

AB3 has ___ bonding pairs, ___ lone pairs, and _____ geometry

3, 0, trigonal planar

AB2E1 has ___ bonding pairs, ___ lone pairs, and _____ geometry

2, 1, bent

Tetrahedral molecular geometries

AB4, AB3E1, AB2E2

AB4 has ___ bonding pairs, ___ lone pairs, and ____ geometry

4, 0, tetrahedral

Tetrahedral bond angles

109.5

AB3E1 has ___ bonding pairs, ___ lone pairs, and ____ geometry

3, 1, trigonal pyramidal

AB2E2 has ___ bonding pairs, ___ lone pairs, and ____ geometry

2, 2, bent

Trigonal bipyramidal molecular geometries

AB5, AB4E1, AB3E2, AB2E3

AB5 has ___ bonding pairs, ___ lone pairs, and ____ geometry

5, 0, trigonal bipyramidal

AB4E1 has ___ bonding pairs, ___ lone pairs, and ____ geometry

4, 1, distorted tetrahedral

AB3E2 has ___ bonding pairs, ___ lone pairs, and ____ geometry

3, 2, t-shaped

AB2E3 has ___ bonding pairs, ___ lone pairs, and ____ geometry

2, 3, linear

Octahedral geometries

AB6, AB5E1, AB4E2

AB6 has ___ bonding pairs, ___ lone pairs, and ____ geometry

6, 0, octahedral

AB5E1 has ___ bonding pairs, ___ lone pairs, and ____ geometry

5, 1, square pyramidal

AB4E2 has ___ bonding pairs, ___ lone pairs, and ____ geometry

4, 2, square planar

Octahedral bond angles

90

When there are 2 lone pairs, they are placed ____ degrees from each other

180