EXAM 2: 08 Molecules In 3d

Question 1

Electron domains are distributed around central atoms to minimize…

Answer 1

Electron-pair repulsion

Question 2

What is the Valence Shell Electron Pair Repulsion model (VSEPR)

Answer 2

A model to represent the arrangement of atoms so that electron pairs are as far from each other as possible

Question 3

What is the bond angle and shape name for AX2

Answer 3

180 angle
Linear shape

Question 4

What is the bond angle and shape name of AX3 (three bonding partners)

Answer 4

Trigonal Planar geometry
120 angles

Question 5

What is the bond angle and shape for AX4 (four bonding partners)

Answer 5

Tetrahedral
109.5 angle

Question 6

What is the bond angle and shape of AX5

Answer 6

Trigonal bipyramid
120 angles between equatorial bonds
90 angles between any pair of equatorial and axial bonds

Question 7

What is an equatorial bond

Answer 7

The three bonds that are arranged in a trigonal plane in a trigonal bipyramidal geometry

Question 8

What is an axial bond

Answer 8

Two bonds that form an axis perpendicular to the trigonal plane
- pointing toward the apexes of the pyramids

Question 9

What is the bond angle and shape name of AX6

Answer 9

Octahedron
Bond angles are 90 or 180

Question 10

What do canonical structures represent

Answer 10

The optimal possible spatial arrangement of atoms bonded to the central atom

Question 11

What is steric number

Answer 11

The number of electron domains around any central atom

Question 12

What is the difference between electron-domain geometry and molecular geometry

Answer 12

Electron geometry is the arrangement and number of electron groups while molecular geometry depends on the number of electron groups and the number of lone pairs
- molecular geometry is more specific

Question 13

What is the molecular geometry of a molecule with a steric number of 2 and zero lone pairs

Answer 13

Linear

Question 14

What is the molecular geometry of a molecule with a steric number of 3 and zero lone pairs

Answer 14

Trigonal planar

Question 15

What is the molecular geometry of a molecule with a steric number of 3 and one being a lone pair

Answer 15

Bent

Question 16

What is the molecular geometry of a molecule with a steric number of 4 with zero lone pairs

Answer 16

Tetrahedral

Question 17

What is the molecular geometry of a molecule with a steric number of 4, one being a lone pair

Answer 17

Trigonal pyramidal

Question 18

What is the molecular geometry of a molecule with a steric number of 4, two being lone pairs

Answer 18

Bent

Question 19

What is the molecular geometry of a molecule with a steric number of 5 and zero lone pairs

Answer 19

Trigonal bipyramidal

Question 20

What is the molecular geometry of a molecule with a steric number of 5, one being a lone pair

Answer 20

Seesaw

Question 21

What is the molecular geometry of a molecule with a steric number of 5 and two lone pairs

Answer 21

T-shape

Question 22

What is the molecular geometry of a molecule with a steric number of 5 and three lone pairs

Answer 22

Linear

Question 23

What is the molecular geometry of a molecule with a steric number of 6 and zero lone pairs

Answer 23

Octahedral

Question 24

What is the molecular geometry of a molecule with a steric number of 6 and one lone pairs

Answer 24

Square pyramidal

Question 25

What is the molecular geometry of a molecule with a steric number of 6 and two lone pairs

Answer 25

Square planar

Question 26

What tells us the electron domain geometry

Answer 26

The steric number Only 5 options: linear, trigonal planar, tetrahedral, trigonal bipyramidal or octahedral

Question 27

What does the molecular geometry depend on

Answer 27

The number of nonbonding pairs (Cannot determine bond angles for lone pairs)

Question 28

Molecules with a steric number of 3 can have what molecular geometries

Answer 28

Trigonal planar or bent

Question 29

Molecules with a steric number of 4 can have molecular geometries of

Answer 29

Tetrahedral, trigonal pyramidal, or bent

Question 30

What are the possible molecular geometries of molecules with a steric number of 5

Answer 30

Trigonal bipyramidal, seesaw, t-shaped, or linear

Question 31

Are nonbonding domains more or less repulsive than bonding domains

Answer 31

More repulsive

Question 32

What are the possible molecular geometries of molecules with a steric number of 6

Answer 32

Octahedral, square pyramidal or square planar

Question 33

Is the repulsion caused by lone pair electron domains greater or less than the repulsion caused by multiple bond domains

Answer 33

Greater

Question 34

Are multiple bonds more or less repulsive than single bonds

Answer 34

Somewhat more repulsive, although less than lone pair

Question 35

Molecules with a steric number or 3 have bond angles close to the canonical angle of…

Answer 35

120

Question 36

Molecules with a steric number of 4 have bond angles close to the canonical angle of…

Answer 36

109.5

Question 37

Molecules with a steric number of 5 have bond angles close to the canonical angles of…

Answer 37

90 and 120

Question 38

Molecules with a steric number of 6 have bond angles near the canonical angle of..

Answer 38

90

Question 39

Molecules are polar if..

Answer 39

They have polar bonds and a geometry such that their bond dipoles do not cancel each other out

Question 40

What are the two conditions that have to be satisfied for a molecule to show a net dipole moment

Answer 40

1. The molecule has to have polar bonds, i.e. bonds between atoms of differing electronegativity. The larger the electronegativity difference, the bigger the magnitude of the resulting bond dipoles. 2. The bond dipoles must not cancel. The bond dipole moments are vectors that have magnitude and direction. The magnitude of the vectors is dictated by the electronegativity differences between bonded atoms. The relative spatial positions of the vectors and their orientation (the direction they points in) is determined by the 3d shape of the molecule

Question 41

Symmetrical molecules with identical atoms bonded to the central atom have ____ net dipole moments, even if they have polar bonds

Answer 41

NO!

Question 42

What shapes are symmetrical molecules where the bond dipoles cancel and the net dipole is zero

Answer 42

Linear, octahedral, square planar, trigonal planar and tetrahedral

Question 43

Along the lone pair axis, where are dipole moment vectors pointing

Answer 43

Away from the nucleus Usually small contributions

Question 44

Molecular dipole moments are..

Answer 44

Vector sums of bond dipoles