FINAL - SECTION 4

Question 1

5 basic electron groups (egg)

Answer 1

• Count the number of electron groups around central atom (bonded atoms + LPo central)
• 2 electron groups = linear (sp)
• 3 electron groups = trigonal planar (sp2)
• 4 electron groups = tetrahedral (sp3)
• 5 electron groups = trigonal bypyramidal (sp3d)
• 6 electron groups = octahedral (sp3d2)

Question 2

Dashed lines

Answer 2

Behind plane

Question 3

Solid line

Answer 3

Infront of plane

Question 4

7 molecular geometry shapes (mg)

Answer 4

• Only count ATOMS bonded to central atom
• Bent
• Linear
• Trigonal pyramidal
• T shape
• Seesaw
• Square planar
• Square pyramidal

Question 5

egg = mg when

Answer 5

All electron groups are atoms

Question 6

egg ≠ atoms when

Answer 6

LP are present

Question 7

BLT sandwich

Answer 7

BP LP
2 1 Bent
2 2
2 3 Linear
3 1 Trigonal pyramidal
3 2 T shape
4 1 Seesaw
4 2 Square planar
5 1 Square pyramidal

Question 8

In diatomic molecules..

Answer 8

Only 1 bond so the bond dipole determines polarity

Question 9

In polyatomic molecules…

Answer 9

The total polarity is determined by bond polarity and bond angle

Question 10

Valence bond theory

Answer 10

Defines covalent bond as an electron density between 2 atoms and the ideal distance occurs with overlap from partially filled atomic orbitals of each atom

Question 11

Sigma bond

Answer 11

Formed head to head by overlap of orbitals (single bonds always)

Question 12

Pi bond

Answer 12

Formed by lateral overlap of 2 lobes of orbital

Question 13

Sigma and pi bond in bonds

Answer 13

• Single bond = 1 sigma bond
• Double bond = 1 sigma bond + 1 pi
• Triple bond = 1 sigma bond + 2 pi

Question 14

Hybridization clues

Answer 14

• Attached to 2 atoms: sp
• Attached to 3 atoms: sp2
• Attached to 4 atoms: sp3
• Attached to 5 atoms: sp3d
• Attached to 6 atoms: sp3d2

Question 15

Molecular orbital theory

Answer 15

Typically used for diatomic molecules or at lease treat it like that (only on valence electrons

Question 16

Bonding molecular orbital

Answer 16

High electron density

Question 17

Antibonding molecular orbital

Answer 17

0 electron density

Question 18

*

Answer 18

High energy antibonding orbital

Question 19

Bond order formula

Answer 19

Bonded electrons - anti bonded electrons/2

Question 20

Bond order 1

Answer 20

Single bond

Question 21

Bond order 2

Answer 21

Double bond

Question 22

Bond order 3

Answer 22

Triple bond

Question 23

Bond order 1/2

Answer 23

Rare usually on H2

Question 24

What does high bond order mean

Answer 24

Strong bond

Question 25

HOMO

Answer 25

Highest energy orbital (has electrons)

Question 26

LUMO

Answer 26

Lowest energy orbital (no electrons)

Question 27

There are 2 versions of molecular orbitals. Why

Answer 27

One of them is for atomic numbers less than 8, the other is atomic numbers 8 or more

Question 28

MO is usually for diatomic molecules so how would you know which versions of diagram to use in an occasion like OF?

Answer 28

Calculate the average and the less electronegative one goes on the left and more electronegative goes on the right

Question 29

Draw both MO

Answer 29

ok

Question 30

Relationship between bonding MO and anti bonding BO energy

Answer 30

Antibonding MO is stronger. so sigma 2p

Question 31

Condensed phase

Answer 31

Solid and liquids are considered condensed phase because they are packed close together but still vibrate

Question 32

Intramolecular force

Answer 32

Force that binds atoms making up molecules

Question 33

Intermolecular force

Answer 33

Force between a molecule

Question 34

3 types of intermolecular force

Answer 34

- Dispersion - Dipole-dipole - H bond

Question 35

Dispersion

Answer 35

Every molecule has it and is the weakest (exhibits small partial charges)

Question 36

Dipole-dipole

Answer 36

Has a partial positive and partial negative. The more polar it is, the stronger dipole it has = high boiling point (harder to pull apart)

Question 37

H bond

Answer 37

Strongest and occurs when a partially positive H is covalently bonded to small electronegative N, O, F

Question 38

Order of increasing strength intermolecular force

Answer 38

London dispersion --> dipole-dipole --> H-bond