solid state

Question 1

typical examples of crystalline solids

Answer 1

sodium chloride (NaCl) and quatz (SiO₂)

Question 2

typical examples of amorphous solids

Answer 2

Glass, rubber and plastics

Question 3

Amorphous silicon is one of the best

Answer 3

photovoltaic material available for conversion of sunlight into electricity

Question 4

examples of crystalline solids in nature

Answer 4

iron Fe, copper Cu, silver Ag, Sulphur S, phosphorus P, iodine I, sodium chloride NaCl, zinc sulphate ZnSO₄, naphthalene

Question 5

crystalline solids classified on the basis of nature of Intermolecular forces

Answer 5

molecular, ionic, metallic and covalent solids

Question 6

examples of polar molecular solids

Answer 6

solid SO₂, solid NH₃

Question 7

The molecules of such solids contain polar covalent bonds between H and

Answer 7

F, O or N atoms

Question 8

typical example of covalent or network solids

Answer 8

Diamond and silicon carbide, graphite

Question 9

cubic- possible variations, axial distances or edge lengths, axial angles, examples

Answer 9

Primitive, Body-centred, Face-centred, a=b=c, α=β=γ=90°, NaCl, Zinc blende, Cu

Question 10

Tetragonal- possible variations, axial distances or edge lengths, axial angles, examples

Answer 10

Primitive, Body-centred, a=b≠c, α=β=γ=90°, White tin, SnO₂, TiO₂, CaSO₄

Question 11

Orthorhombic- possible variations, axial distances or edge lengths, axial angles, examples

Answer 11

Primitive, Body-centred, Face-centred, End-centred, a≠b≠c, α=β=γ=90°, Rhombic sulphur, KNO₃, BaSO₄

Question 12

Hexagonal- possible variations, axial distances or edge lengths, axial angles, examples

Answer 12

Primitive, a=b≠c, α=β=90°
γ=120°, Graphite, ZnO, CdS

Question 13

Rhombohedral or trigonal- possible variations, axial distances or edge lengths, axial angles, examples

Answer 13

Primitive, a=b=c, α=β=γ≠90°, Calcite (CaCO₃), HgS (cinnabar)

Question 14

Monoclinic- possible variations, axial distances or edge lengths, axial angles, examples

Answer 14

Primitive, End-centred, a≠b≠c, α=γ=90°
β≠90°, Monoclinic sulphur, Na₂SO₄.10H₂O

Question 15

Triclinic- possible variations, axial distances or edge lengths, axial angles, examples

Answer 15

Primitive, a≠b≠c, α≠β≠γ≠ 90°, K₂Cr₂O₇, CuSO₄.5H₂O, H₃BO₃

Question 16

Hexagonal close packed (hcp) structure is found in many metals like

Answer 16

magnesium and zinc

Question 17

cubic close packed (ccp) or face- centred cubic (fcc) structure is found in metals like

Answer 17

copper and silver crystalline

Question 18

how much space is filled in fcc/ccp?

Answer 18

74%

Question 19

In hcp or fcc, each sphere is in contact of

Answer 19

twelve spheres

Question 20

Packing efficiency of bcc is

Answer 20

68%

Question 21

PE of simple cubic unit cell

Answer 21

52.4%

Question 22

single crystals are formed when the process of crystallisation occurs at

Answer 22

extremely slow rate

Question 23

crystal defects are of two types-

Answer 23

point defects and line defects

Question 24

point defects can be classified into three types-

Answer 24

stoichiometric defects
impurity defect
non-stoichiometric defect

Question 25

Ionic solids must always maintain

Answer 25

electrical neutrality

Question 26

Frenkel defect is also called

Answer 26

dislocation defect

Question 27

Frenkel defect does not change

Answer 27

the density of the solid

Question 28

Frenkel defect is shown by ionic substance in which there is a

Answer 28

large difference in the size of ions

Question 29

example of substance which show Frenkel defect

Answer 29

ZnS, AgCl, AgBr and AgI due to small size of Zn²⁺ and Ag²⁺ ions

Question 30

In Schottky Defect, in order to maintain electrical neutrality

Answer 30

the number of missing cations and anions are equal to the number of missing

Question 31

examples of Schottky defect

Answer 31

NaCl, KCl, CsCl and AgBr

Question 32

examples of Impurity defects

Answer 32

NaCl and SrCl₂; CdCl₂ and AgCl

Question 33

what color does the crystal of NaCl imparts?

Answer 33

yellow

Question 34

Example of metal excess defect due to anionic vacancies

Answer 34

NaCl (yellow), LiCl (pink), KCl (violet or lilac)

Question 35

example of metal excess due to the presence of extra cations

Answer 35

ZnO (white) turns into Zn²⁺ and loses oxygen (yellow)

Question 36

example of metal deficiency defect

Answer 36

FeO which is mostly found with a composition of Fe₀.₉₅O

(It may actually range from Fe0.93O to Fe0.96O)

Question 37

Typical compounds of groups 13-15 are

Answer 37

InSb, AlP
and GaAs

Question 38

which semiconductors have very fast response and have revolutionized the design of semiconductor devices?

Answer 38

GaAs

Question 39

examples of groups 12 – 16 compounds

Answer 39

ZnS, CdS, CdSe and HgTe

Question 40

TiO, CrO2 and ReO3 behave like

Answer 40

metals

Question 41

Rhenium oxide, ReO3 is like

Answer 41

metallic copper in its conductivity and appearance

Question 42

Certain other oxides like VO, VO2, VO3 and TiO3
show

Answer 42

metallic or insulating properties depending on temperature

Question 43

examples of paramagnetic compounds

Answer 43

O2, Cu2+, Fe3+, Cr3+

Question 44

what few substances are attracted very strongly by a magnetic field?

Answer 44

Iron, cobalt, nickel, gadolinium and CrO2

Question 45

which substance show antiferromagnetisn

Answer 45

MnO

Question 46

examples of ferrimagnetism

Answer 46

Fe3O4 (magnetite) and ferrites like MgFe2O4 and
ZnFe2O4

Question 47

zone refining is the method used to purify

Answer 47

crystals or metals