HARD

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Calculate the packing fraction of a fluorite structure. (i.e., ${CaF}_{2}$ solid). Assuming perfect fit situation.

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Important Questions on Solid State

EASY

Chemistry>Physical Chemistry>Solid State>Structure of Ionic Compounds

What are the coordination numbers (C.N.) of

{Ca}^{2 +}

and

F^{-}

ion in calcium fluoride

({CaF}_{2})

crystal structure ?

EASY

Chemistry>Physical Chemistry>Solid State>Structure of Ionic Compounds

What is the value of radius ratio of ionic crystal having coordination number six?

MEDIUM

Chemistry>Physical Chemistry>Solid State>Structure of Ionic Compounds

If the edge length of a body centred unit cell is

400 pm,

what will be the approximate radius of the atom present in it? (in pm)

MEDIUM

Chemistry>Physical Chemistry>Solid State>Structure of Ionic Compounds

Ionic radii of cation

A^{+}

and anion

B^{-}

are

102

and

181 pm

respectively. These ions are allowed to crystallize into an ionic solid. This crystal has cubic close packing for

B^{-} . A^{+}

is present in all octahedral voids. The edge length of the unit cell of the crystal

AB

is___

pm

EASY

Chemistry>Physical Chemistry>Solid State>Structure of Ionic Compounds

A unit cell of calcium fluoride has four calcium ions. The number of fluoride ions in the unit cell is

MEDIUM

Chemistry>Physical Chemistry>Solid State>Structure of Ionic Compounds

In a compound, atoms of element

Y

form

ccp

lattice and those of element

X

occupy

\frac{2}{3}

of tetrahedral voids. The formula of the compound will be

EASY

Chemistry>Physical Chemistry>Solid State>Structure of Ionic Compounds

What is the co-ordination number of

{Cl}^{-}

NaCl

crystal ?

EASY

Chemistry>Physical Chemistry>Solid State>Structure of Ionic Compounds

An intrinsic semiconductor is converted into

n

-type extrinsic semiconductor by doping it with:-

MEDIUM

Chemistry>Physical Chemistry>Solid State>Structure of Ionic Compounds

The arrangement of X^- ions around A⁺ ion in solid AX is given in the figure (not drawn to scale). If the radius of X^- is 250 pm, the radius of A⁺ is

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MEDIUM

Chemistry>Physical Chemistry>Solid State>Structure of Ionic Compounds

The radius of

K^{+}

133 pm

and that of

{Cl}^{-}

181 pm

. The volume of the unit cell of

KCl

expressed in

10^{- 22} {cm}^{3}

is:

EASY

Chemistry>Physical Chemistry>Solid State>Structure of Ionic Compounds

The barrier potential of a p-n junction depends on:

(a)

type of semi-conductor material

(b)

amount of doping

(c)

temperature
Which one of the following is correct?

HARD

Chemistry>Physical Chemistry>Solid State>Structure of Ionic Compounds

Consider an ionic solid

MX

, with

NaCl

structure. Construct a new structure

(Z)

, whose unit cell is constructed from the unit cell of

MX

, following the sequential instructions given below. Neglect the charge balance.

(i)

Remove all the anions

(X)

, except the central one.

(ii)

Replace all the face centered cations

(M)

, by anions

(X)

(iii)

Remove all the corner cations

(M)

(iv)

Replace the central anion

(X)

, with cation

(M)

.

The value of

(\frac{n u m b e r o f a n i o n s}{n u m b e r o f c a t i o n s})

Z

is _____.

MEDIUM

Chemistry>Physical Chemistry>Solid State>Structure of Ionic Compounds

The contribution to the total current in a semiconductor, due to electrons and holes are

0.75

and

0.25

respectively. The drift velocity of electrons is

\frac{3}{2}

times that of holes at this temperature. Then the ratio between electron concentration and hole concentration is

HARD

Chemistry>Physical Chemistry>Solid State>Structure of Ionic Compounds

Number of unit cells present in a cubic shaped ideal crystal of

NaCl

of mass

1.00 g

is [Molecular mass

= 58.5

]

HARD

Chemistry>Physical Chemistry>Solid State>Structure of Ionic Compounds

The cubic unit cell structure of a compound containing cation $M$ and anion $X$ is shown below. When compared to the anion, the cation has smaller ionic radius. Choose the correct statement(s).

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