solid state

Question 1

the simplest unit which can repeat itself over and over again to form a lattice

Answer 1

unit cell

Question 2

3 types of cubic unit cells

Answer 2

simple cubic, body centered cubic, face centered cubic

Question 3

which one of the cubic unit cells is primitive

Answer 3

simple cubic

Question 4

number of atoms in simple cubic cell

Answer 4

8

Question 5

nearest neighbors of an atom in simple cubic unit

Answer 5

6

Question 6

number of atoms in a bcc cell

Answer 6

9

Question 7

nearest neighbor in bcc (Coordination Number)

Answer 7

8

Question 8

no. of atoms in fcc structure

Answer 8

14

Question 9

nearest neighbor in fcc

Answer 9

12

Question 10

what is packing efficiency/ packing fraction

Answer 10

space occupied by atoms in a unit cell

Question 11

packing fraction in simple cubic

Answer 11

52.4%

Question 12

packing fraction in bcc

Answer 12

68%

Question 13

packing fraction in fcc

Answer 13

74%

Question 14

2d square closed packing pattern (scp)

Answer 14

AAAA….

Question 15

2d hexagonal closed packing pattern (hcp)

Answer 15

ABAB….

Question 16

3d simple cubic packing

Answer 16

AAAA….

Question 17

3D cubic closed packing (ccp or fcc)

Answer 17

ABCABC….

Question 18

3D hexagonal closed packing

Answer 18

ABABAB….

Question 19

types of voids

Answer 19

triangular, tetrahedral, octahedral, cubical void

Question 20

coordination number of triangular void

Answer 20

3

Question 21

triangular void is found in

Answer 21

2d hcp

Question 22

coordination number of tetrahedral void

Answer 22

4

Question 23

tetrahedral void is found in

Answer 23

fcc, 3d hcp

Question 24

coordination number of octahedral void

Answer 24

6

Question 25

octahedral void is found in

Answer 25

fcc, 3d hcp

Question 26

coordination number of cubical void

Answer 26

8

Question 27

cubical void is found in

Answer 27

simple cubic

Question 28

size of void in descending order

Answer 28

triangular> tetrahedral> octahedral> cubical

Question 29

if number of atoms per unit cell (Z eff)= N then

Answer 29

tetrahedral void= 2N; octahedral void= N [only in 3d hcp and fcc/ccp]

Question 30

formula for density of unit cell

Answer 30

``` Z x M/ Na x a3 where Z= no. of atoms per unit cell M= molar mass Na= Avogadro's no.= 6 x 10^23 a= edge length (cm) ```

Question 31

when equal number of crystals are missing from the crystal

Answer 31

Schottky defect

Question 32

examples of Schottky defect

Answer 32

NaCl, KCl, CSCl, KBr

Question 33

when one of the ions (usually cation) is dislocated from lattice point to interstitial site

Answer 33

Frenkel/ dislocation defect

Question 34

examples of Frenkel defect

Answer 34

ZnS, AgBr, AgCl

Question 35

_______ exhibits both schottky and frenkel defects

Answer 35

AgBr

Question 36

what are the 2 stoichiometric defects

Answer 36

schottky and frenkel

Question 37

what are the 2 non stoichiometric defects

Answer 37

metal excess, metal deficient

Question 38

2 types of metal excess defects

Answer 38

1. anion vacancy | 2. extra cation

Question 39

foreign atoms that replace some of the atoms making up the solid or that squeeze into the interstices

Answer 39

impurity defect

Question 40

property of obtaining different values when observing or measuring something from different directions.

Answer 40

anisotropic

Question 41

property of obtaining same values when observing or measuring something from different directions.

Answer 41

isotropic

Question 42

what are crystalline solids

Answer 42

- long range order - anisotropic - sharp melting point - eg: NaCl, quartz

Question 43

what are amorphous solids

Answer 43

- short range order - isotropic - tendency to flow ∴ pseudo solids - eg: glass, rubber, plastic, quartz glass

Question 44

what is anisotropy

Answer 44

materials whose properties differ when tested in different directions

Question 45

types of crystalline solids

Answer 45

molecular ionic metallic covalent