Exam 2 Review

Question 1

nonpolar covalent bond

Answer 1

electrons are shared equally between two atoms, EN difference of 0-0.4

Question 2

polar covalent bond

Answer 2

electrons shared unequally between atoms, EN difference of 0.4-2.0

Question 3

ionic bond

Answer 3

electrons are essentially transferred from one atom to another; EN difference of 2+

Question 4

% ionic character

Answer 4

measured dipole moment of bond/dipole moment if e- were completely transferred (6.2 D) (no bond is 100% ionic, 50+% is considered an ionic bond)

Question 5

formal charge

Answer 5

ve - # of nonbonding e - # of bonds (charge an atom would have if all bonding e were shared equally)`

Question 6

rules for formal charge

Answer 6

1. sum of all formal charges should = 0 in a neutral molecule
2. sum of all formal charges in an ion must equal charge of ion
3. small (or 0) formal charges on individual atoms are better than larger ones
4. when unavoidable, negative formal charge should reside on the most EN atom

Question 7

2 e groups, 2 bonding groups, 0 lone pairs

Answer 7

E: linear, M: linear, bond angle: 180

Question 8

3 e groups, 3 bonding groups, 0 lone pairs

Answer 8

E: trigonal planar, M: trigonal planar, bond angles: 120

Question 9

3 e groups, 2 bonding groups, 1 lone pair

Answer 9

E: trigonal planar, M: bent, bond angles: <120

Question 10

4 e groups, 4 bonding groups, 0 lone pairs

Answer 10

E: tetrahedral, M: terahedral, bond angles: 109.5

Question 11

4 e groups, 3 bonding groups, 1 lone pair

Answer 11

E: tetrahedral, M: trigonal pyramidal, bond angles: <109.5

Question 12

4 e groups, 2 bonding groups, 2 lone pairs

Answer 12

E: tetrahedral, M: bent, bond angles: <109.5

Question 13

5 e groups, 5 bonding pairs, 0 lone pairs

Answer 13

E: trigonal bipyramidal, M: trigonal bpyramidal, bond angles: 120 (equatorial) 90 (axial)

Question 14

5 e groups, 4 bonding pairs, 1 lone pair

Answer 14

E: trigonal bipyramidal, M: seesaw, bond angles: <120 (equatorial) <90 (axial)

Question 15

5 e groups, 3 bonding pairs, 2 lone pairs

Answer 15

E: trigonal bipyramidal, M: T-shaped, bond angles: <90

Question 16

5 e groups, 2 bonding pairs, 3 lone pairs

Answer 16

E: trigonal bipyramidal, M: linear, bond angles: 180

Question 17

6 e groups, 6 bonding pairs, 0 lone pairs

Answer 17

E: octahedral, M: octahedral, bond angles: 90

Question 18

6 e groups, 5 bonding pairs, 1 lone pair

Answer 18

E: octahedral, M: square pyramidal, bond angles: <90

Question 19

6 e groups, 4 bonding pairs, 2 lone pair

Answer 19

E: octahedral, M: square planar, bond angles: 90

Question 20

sp hybridization

Answer 20

linear, 2 e groups

Question 21

sp2 hybridization

Answer 21

trigonal planar, 3 e groups

Question 22

sp3 hybridization

Answer 22

tetrahedral, 4 e groups

Question 23

sp3d hybridization

Answer 23

trigonal bipyramidal, 5 e groups

Question 24

sp3d2 hybridization

Answer 24

octahedral, 6 e groups

Question 25

sigma bond

Answer 25

orbitals overlap end to end

Question 26

pi bond

Answer 26

orbitals overlap side by side

Question 27

MO of B2, C2, N2

Answer 27

pi MO then sigma MO

Question 28

MO of O2, F2, Ne2

Answer 28

sigma MO then pi MO