2nd

Question 1

bond that’s between diff electronegative atoms is aaa

Answer 1

polarised bond

Question 2

what does polarised mean

Answer 2

2 atoms involved in a bond have different electronegative properties.
this means that electrons aren’t shared evenly between atoms

Question 3

more electronegative atom will have aaa

Answer 3

partially negative charge

Question 4

electronegativity series (pauling scale)

Answer 4

F O Cl N C H Li

Question 5

carbon is a … molecule

Answer 5

tetravalent!!
forms 4 bonds
mix of double, single, triple

Question 6

trivalent carbon examples

Answer 6

carbocation +
carbanion -

Question 7

C-C bond angle

Answer 7

109

Question 8

C=C bond angle

Answer 8

120

Question 9

C triple C bond angle

Answer 9

180 linear

Question 10

bond angle in benzene and cyclohexane

Answer 10

all equal

Question 11

same side of double bond

Answer 11

cis

Question 12

opposite side of double bond

Answer 12

trans

Question 13

C-C bond length

Answer 13

1.57Å

Question 14

C=C bond length

Answer 14

1.35Å

Question 15

C triple C bond length

Answer 15

1.21Å

Question 16

Heisenburg uncertainty principle tells us what about electrons

Answer 16

we cannot know the precise location of an electron at any given moment.

we say they have a probability of being in a certain area (orbital)

Question 17

energy and location of electrons are

Answer 17

quantised (whole numbers)
the probability of finding an electron somewhere is not random

Question 18

pauli exclusion principle

Answer 18

electrons in one orbital must have opposite spins.
two electrons with the same spin cannot occupy the same orbital.

Question 19

why is there an energy penalty for paired electrons

Answer 19

paired electrons experience the destabilising effect of inter electron repulsion this means they require more energy to stay paired up in that configuration as it is less favourable than being unpaired.

Question 20

hunds rule

Answer 20

electrons will only pair up if they have to + if there’s no other possible electronic configuration for that energy level.

Question 21

what gives rise to bonding and molecular orbitals

Answer 21

the valence electrons

Question 22

why is C tetravalent

Answer 22

it’s electron configuration! 6 e-
1s is full
2s is full
2p has 4 electrons missing
C must bond 4 times to fill orbitals

Question 23

what is orbital hybridisation

Answer 23

helps us understand how atomic orbitals (where electrons are most likely to be found) are mixed to create new hybrid orbitals.

Question 24

what is the point of orbital hybridisation

Answer 24

help us explain observed shape and bonding patterns in molecules

Question 25

different types of hybridisation

Answer 25

sp3
sp2
sp

Question 26

sp3 orbital

Answer 26

1 s orbital
3 p orbitals

forms 4 hybrid orbitals all with the same energy

25% s character,, 75% p character

Question 27

different p orbitals in sp3 hybrid orbitals

Answer 27

px, py, pz

Question 28

shape of sp3 hybrid orbitals

Answer 28

tetrahedral 109

Question 29

methane hybridisation

Answer 29

4 sp3 hybrids on carbon
4 s orbitals on H
BOND TOGETHER
full orbitals

Question 30

singlebond between 2 Carbons

Answer 30

2 sp3 hybrids bond to form a single bond // sigma bond // sp3 sp3 bond

Question 31

what is a sigma bond

Answer 31

covalent bond
2 atomic orbitals overlap head on forming a strong bond between atoms
found in single bonds
strongest covalent bond.

Question 32

pi bond

Answer 32

cool sideways connection.
sideways connection between orbitals.
electron density is concentrated above and below the bond axis.
found in double + triple bonds with the sigma bond

Question 33

what is the bond axis

Answer 33

imaginary line between nuclei of atoms
connects two nuclei + keeps them in a bond
runs through the sigma bond
helps us visualise bond orientation and overlapping orbitals

Question 34

sp3 is aaaa

Answer 34

single bond

Question 35

sp2 hybrid

Answer 35

1 s orbital
2 out of the 3 available p orbitals

double bond

Question 36

sp2 hybrid used p orbitals

Answer 36

2px
2py

one non-hybridised 2p orbital

Question 37

sp2 hybrid composition

Answer 37

33% s
66% p

2pz remains non hybridised

Question 38

2pz and sp2 hybrid difference

Answer 38

they will lie of different axis.
2pz will be slightly higher as it has no s orbital character

Question 39

sp2 hybrid angle and shape

Answer 39

sp2 are in the same plane
120* angle
2pz orbital is 90 to them on a different plane

imagine a propeller
( blades = sp2, middle = 2pz )

Question 40

head to head interaction of 2 sp2 hybrid orbital gives a .. bond

Answer 40

sigma

Question 41

interaction between the two non hybridised 2pz orbitals gives a

Answer 41

pi bond!!!

weaker than sigma bond as it’s a side by side interaction, not head on overlap.

Question 42

sp hybridisation

Answer 42

1 s orbital
1 out of the 3 available p orbitals
2 non hybridised p orbitals ( 2px, 2pz)

Question 43

sp hybrid orbitals account for

Answer 43

CC triple bonds

Question 44

NH3 has what hybridisation

Answer 44

sp3
107.3
N has 1 more electron than C. this means it has a full sp3 orbital -> this is the lone pair.

Question 45

O has what hybridisation

Answer 45

O has 1 more electron than N so 2 sp3 must be fully occupied.
this means O has 2 lone pairs.
104.5

Question 46

why can’t double bonds rotate?

Answer 46

p orbitals cannot efficiently overlap in pi bonds unlike the sigma bond.

allows isomers to form

Question 47

why can single bonds rotate

Answer 47

there is efficient overlap of the sigma bond.

rotation still causes changes in energy (newman projection)