topic 1🅱️

Question 1

solid

Answer 1

state of matter
particles are arranged in a way that makes their shape + volume stable

Question 2

what is solid state chem

Answer 2

it’s about making/ preparing solids
structure of solids
properties of solids

Question 3

ionic bonding

Answer 3

regular arrays of positively and negatively charged ions

electrostatic forces of interaction

Question 4

covalent bonding

Answer 4

atoms in the compound share electrons in order to obtain an octet figuration.

lewis model + MO bonding theory

Question 5

why do we use the terms ionic and covalent character

Answer 5

bc bonding is a spectrum.

it’s never either the 2 extremes but a combo of both

Question 6

types of solid: molecular solid

Answer 6

• solid made up of molecules
• bonds are covalent (strong)
• intermolecular bonds are weaker (H, DD, VDW
• soft materials
• low melting points (only the intermolecular need to be broken to change state)

Question 7

in molecular solids,, what interaction needs to be broken in order for them to change state

Answer 7

intermolecular interaction!!!
HYDROGEN, DIPOLE DIPOLE,, VDW

the covalent bonding (intra) doesn’t need to be broken

Question 8

types of molecular solids

Answer 8

Iodine
I2 = covalently bonded

I2 —- I2 (van der waals interactions)

Question 9

describe iodine solid

Answer 9

covalent between I and I
VDW between I2
VDW = strong enough for iodine to be solid at room temp. (lots of e-)
- solid sublimes easily into vapour
- low 113.7* melting point

Question 10

sublimation // sublimes meaning

Answer 10

going from solid to gas // vapour
doesn’t go through the liquid phase // state

Question 11

another example for a molecular solid

Answer 11

sulfur

Question 12

describe sulfur

Answer 12

• solid in ambient conditions
• contains S8 ring molecules
• covalent S and S
• VDW // dispersion between S8
• soft, bright, yellow at room temp
• low mp of 115.2*
• sublimes easily

Question 13

what are covalent network solids

Answer 13

• covalently bonded atoms that form a continuous infinite network

Question 14

what can form covalent network solids

Answer 14

elements (C)
compounds (SiO2)

Question 15

describe covalent network solids

Answer 15

high melting + boiling points
hard
brittle (covalent bonds must be broken to change state)

Question 16

examples of covalent network solids

Answer 16

graphite
diamond
quartz
a-crietobalite

Question 17

further examples of covalent network solids

Answer 17

carbon!!
it has many allotropes

Question 18

what’s an allotrope

Answer 18

different solid stage structures of the same element

Question 19

describe C,, CNS : graphite

Answer 19

• layers of sp2 hybrid C
• high mp (covalent within layers)
• pencils + lubricants (VDW between layers - slips)
• conductive ( delocalised e- between layers)

Question 20

CNS: C : diamond

Answer 20

• sp3 hybrids (single bonds)
• 4 covalent bonds each (hard solid + high mp)
• no delocalised e- : not conductive

Question 21

CNS: C : graphene

Answer 21

single sheet of graphite
similar properties to graphite (high mp, conductive )
very strong
very light

Question 22

CNS : C : fullerenes

Answer 22

nanotubes
rolled sheet of graphite
strong, light, conductive

buckyballs: lower mp ( VDW between spheres)

Question 23

difference between fullerenes and graphene

Answer 23

graphene is a flat sheet of graphite
fullerene is a rolled sheet of graphite

fullerenes can also include nanotubes or buckyballs

Question 24

CNS: SiO2 (silicone dioxide)

Answer 24

• covalent bonds between Si and O
• many diff know structures (polymorphs)

Question 25

what is a polymorph

Answer 25

different solid stage structures of the same compound

Question 26

what are the 2 polymorphs of SiO2

Answer 26

quartz a-cristobalite

Question 27

describe quartz : CNS (SiO2)

Answer 27

most common polymorph natural mineral most common mineral on the earth

Question 28

describe a-cristobalite : CNS: SiO2

Answer 28

common polymorph of SiO2 also has its own polymorphs at high and low temperatures

Question 29

describe a metallic solid

Answer 29

- cations in a sea of delocalised electrons - interactions between cations and e- = strong metallic bonding - hard solids + mp + bp due to strong metallic bonding - only valence e- contribute to the bonding + are delocalised - conductive in solid + molten form

Question 30

ionic solid type of solid

Answer 30

- cations and anions - electrostatic forces between oppositely charged ions holds them together - high melting + bp - hard and brittle (strong ionic bonds) - conductive when molten or dissolved in aq solution

Question 31

what elements are more likely to form ionic compounds

Answer 31

those that are more easily ionised more readily ionised aka lower ionisation energies.

Question 32

example of an ionic solid

Answer 32

NaCl sodium chloride Na+ and Cl-

Question 33

what is a crystal

Answer 33

a crystalline solid

Question 34

what is a crystal or a crystalline solid

Answer 34

solid consisting of a regular and repeating array of atoms, molecules, ions. extend in 3 dimensions to give an ordered structure

Question 35

what type of symmetry does a crystal have

Answer 35

translational symmetry

Question 36

what is translational symmetry

Answer 36

a movement, shift or slide in a specific direction by a specific distance without rotation or reflection

Question 37

what is a unit cell in a crystal

Answer 37

the smallest repeating unit of a crystal

Question 38

how many parameters is a unit cell described with

Answer 38

6

Question 39

what 6 parameters are used to describe a unit cell

Answer 39

3 vector lengths : a b c 3 angles : a B y

Question 40

what the relationship between the crystal parameters in a cubic unit cell

Answer 40

a = b = c a = B = y = 90*

Question 41

how is a full crystal structure generated

Answer 41

when the unit cell is translated in 3 directions when translational symmetry occurs me

Question 42

what are the 4 other basic crystal symmetry

Answer 42

- mirror symmetry - inversion symmetry - rotational symmetry - rotary inversion symmetry

Question 43

combo of what allows us to build up an entire crystal structure

Answer 43

combo of all the symmetries - mirror - rotation - translation - inversion - rotary inversion

Question 44

1 fold in rotational symmetry

Answer 44

360*

Question 45

2 fold in rotational symmetry

Answer 45

180

Question 46

4 fold in rotatory symmetry

Answer 46

90

Question 47

how can we determine the crystal structure // the structure of crystalline solids

Answer 47

analytical technique - x ray crystallography

Question 48

how does the analytical technique of x ray crystallography determine the solid structure of crystalline solids

Answer 48

- x ray beam is shone on crystal - diffraction occurs as x ray beam wavelength is similar to the order of gaps between atoms - detector is used to identify the diffraction pattern which is mathematically related to the structure of a crystal

Question 49

close packing + atoms :: what will always be present

Answer 49

small gaps will always be present no matter how tightly u pack the atoms together

Question 50

what is the most efficient way for atoms to pack together to minimise the amount of space between them

Answer 50

close packing it minimises the amount of space between them

Question 51

close packing : A

Answer 51

looks like a bunch of flower heads each atom is in contact with 6 atom neighbours one close packed layer

Question 52

close packing AB

Answer 52

spheres in layer 2 sit between the first layers gaps 2 close packed layers

Question 53

3 close packed sphere layers

Answer 53

2 options: - ABA : spheres in 3 sits directly above layer 1 ( hexagonal close packing) flower up front,, gaps go all the way through - ABC : spheres in layer 3 sit directly above layer one gaps (cubic close packing) (no spheres are directly above each other,, all layers are different,, no straight through gaps)

Question 54

what repeats does cubic close packing (ccp) aka the triangle top shape have

Answer 54

ABCABCABCABCABCABCABC cubic for c!! each layer is different,, no atoms are directly above other atoms,, no straight through gaps.

Question 55

what repeat does hexagonal close packing have (aka the flower on top)

Answer 55

ABABABABABABABABABAB

Question 56

most common close packing arrangements

Answer 56

CCP HCP

Question 57

in how many directions must a unit cell be translated in order to general the full crystal structure

Answer 57

must be translated into three directions

Question 58

what is the ‘cubic’ is ccp referring to

Answer 58

the cubic symmetry of its structure - a=b= c - a = B = y = 90*

Question 59

how else can the ccp unit cell be called

Answer 59

face centred cubic (fcc)

Question 60

what are other important cubic cell units called

Answer 60

body centred cubic (bcc) primitive cubic (pc)

Question 61

are bcc or pc close packed

Answer 61

nope!! neither of them are close packed

Question 62

what is face centred cubic (fcc)

Answer 62

atoms are on all cube vertices and in the centre of the faces

Question 63

what is body centred cubic (bcc)

Answer 63

atoms are on all vertices of the cube 1 atom in the centre of the cube

Question 64

what is primitive cubic

Answer 64

atoms are seen on all vertices of the cube only

Question 65

what does the hexagonal in hcp stand for

Answer 65

the hexagonal symmetry of the structure

Question 66

what conditions are seen in the unit cell or a hexagonal structure

Answer 66

- vectors: a=b NOT c - angles: y=120

Question 67

what elements can adopt the CCP HCP BCC

Answer 67

metallic elements!! phase transitions can occur between different structures under ambient temp and pressure

Question 68

what structure does metallic Cu^0 adopt

Answer 68

CCP FCC

Question 69

what structure does metallic Ti ^0 adopt

Answer 69

hcp

Question 70

what structure does metallic Iron m,, Fe^0 adopt

Answer 70

bcc

Question 71

make it known!! ccp is

Answer 71

cubic close packing also known as face centred cubic

Question 72

ccp is

Answer 72

cubic close packing

Question 73

ccp can also be called

Answer 73

fcc

Question 74

what is fcc

Answer 74

face centred cubic also known as cubic close packing

Question 75

what is hexagonal close packing

Answer 75

ABABABAB

Question 76

ccp is called,,, and how many different ones are there

Answer 76

cubic close packing also known as face centred cubic - body centred cubic - primitive cubic

Question 77

which structures are closely packed

Answer 77

cubic close packing ABC (face centred cubic) hexagonal close packing ABAB

Question 78

which structures arent closely packed

Answer 78

body centred cubic primitive cubic

Question 79

which holes can u see all the way through

Answer 79

hexagonal closed packing ababababa H exagonal for Holes 3 above and 3 below

Question 80

which holes can u not see all the way through

Answer 80

cubic close packing 3 above 1 below C ubic for ABC

Question 81

coordination number of an atom in hcp

Answer 81

12 3 above 6 3 above

Question 82

coordination number of atoms in a ccp

Answer 82

12 3 above 6 3 above

Question 83

bcc coordination number

Answer 83

8

Question 84

primitive coordination number

Answer 84

6

Question 85

primitive cubic can also be called what

Answer 85

simple cubic atoms on corners only

Question 86

what is packing efficacy

Answer 86

percentage of the structure that is filled by atoms

Question 87

for a bcc: packing efficacy

Answer 87

u need to put a bit more effort in. first find x by doing L2 + L2 = X2 then do X2 + L2 = 4r2 then do the whole atom volume thing and do L3 to find the volume

Question 88

number of atoms in ccp

Answer 88

4

Question 89

number of atoms in hcp

Answer 89

2

Question 90

number of atoms in bcc

Answer 90

2

Question 91

number of atoms in primitive cubic // simple cubic

Answer 91

1

Question 92

packing effficacy of hcp and ccp

Answer 92

74%

Question 93

packing efficacy of bcc

Answer 93

68%

Question 94

packing efficacy of primitive

Answer 94

52.4%

Question 95

close packed structures intersitital sites

Answer 95

tetrahedral octahedral

Question 96

how many octahedral sites per atom

Answer 96

1 site is bonded to 6 atoms 3 below 3 above can see through

Question 97

how many tetrahdral sites per atom

Answer 97

2 site is bonded to 4 atoms 3 above 1 below cant see through

Question 98

length of ccp/fcc

Answer 98

8 1/2 r cube this to get volume