A metallic element exists as cubic lattice. Each edge of the unit cell is 2.88 $\stackrel{0}{A}$. The density of the metal is 7.20 g $c{m}^{-3}$. How many unit cell will be present in 100 g of the metal -

(A) $6.85×{10}^{2}$

(B) $5.82×{10}^{23}$

(C) $4.37×{10}^{5}$

(D) $2.12×{10}^{6}$

Concept Questions :-

Density/Formula/packing fraction/ Semiconductors
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

Iron crystallizes in a b.c.c. system with a lattice parameter of 2.861 $\stackrel{0}{A}$. Calculate the density of iron in the b.c.c. system (Atomic weight of Fe = 56, ${N}_{A}=6.02×{10}^{23}mo{l}^{-1}$)

(A) 7.92g $m{l}^{-1}$

(B) 8.96g $m{l}^{-1}$

(C) 2.78g $m{l}^{-1}$

(D) 6.72g $m{l}^{-1}$

Concept Questions :-

Density/Formula/packing fraction/ Semiconductors
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

An alloy of copper, silver and gold is found to have copper constituting the ccp lattice. If silver atoms occupy the edge centres and gold is present at body centre, the alloy has a formula-

(A) $C{u}_{4}A{g}_{2}Au$

(B) $C{u}_{4}A{g}_{4}Au$

(C) $C{u}_{4}A{g}_{3}Au$

(D) $CuAgAu$

Concept Questions :-

Density/Formula/packing fraction/ Semiconductors
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

Frenkel defect is not found in the halides of alkali metals because alkali metals have

1. high electropositivity

3. high reactivity

4. ability to occupy interstitial sites

Concept Questions :-

High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

Iodine crystal are-

(A) Metallic solid

(B) Ionic solid

(C) Molecular solid

(D) Covalent solid

Concept Questions :-

Introduction and Type of Crystal System
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

A solid PQ have rock salt type structure in which Q atoms are at the corners of the unit cell. If the body centred atoms in all the unit cells are missing, the resulting stoichiometry will be-

(A) PQ

(B) $P{Q}_{2}$

(C) ${P}_{3}{Q}_{4}$

(D) ${P}_{4}{Q}_{3}$

High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

8 : 8 co-ordination of CsCl is found to change into 6 : 6
co-ordination on:

(a) applying pressure
(b) increasing temperature
(c) both (a) and (b)
(d) none of these

Concept Questions :-

Introduction and Type of Crystal System
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

At room temperature, sodium crystallises in a body centred cubic cell with a 4.24 $\stackrel{0}{A}$. The theoretical density of sodium is- (Atomic mass of sodium=23.0 g $mo{l}^{-1}$)

(A)

(B)

(C)

(D)

Concept Questions :-

Density/Formula/packing fraction/ Semiconductors
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

Which is amorphous solids-

(A) Rubber

(B) Plastic

(C) Glass

(D) All

Concept Questions :-

Introduction and Type of Crystal System
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

In the unit cell of an fcc system the number of octahedral and tetrahedral holes are

(A) 4,4

(B) 4, 8

(C) 1, 8

(D) 4, 1

Concept Questions :-