The correct order of the packing efficiency in different types of unit cells is-

1.  Fcc < Bcc < Simple cubic

2.  Fcc > Bcc > Simple cubic

3.  Fcc < Bcc > Simple cubic

4.  Bcc < Fcc > Simple cubic

Subtopic:  Density & Packing Fraction |
86%
From NCERT
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The most efficient packing is present in -

1. HCP and BCC

2. HCP and CCP

3. BCC and CCP

4. BCC and Simple cubic cell

Subtopic:  Density & Packing Fraction |
82%
From NCERT
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An element has a body-centered cubic (BCC) structure with a cell edge of 288 pm. The atomic radius is:

1. $\frac{\sqrt{2}}{4}×288$ pm

2. $\frac{4}{\sqrt{3}}×288$ pm

3. $\frac{4}{\sqrt{2}}×288$ pm

4. $\frac{\sqrt{3}}{4}×288$ pm

Subtopic:  Introduction & Crystal System | Density & Packing Fraction |
81%
From NCERT
NEET - 2020
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The formula of nickel oxide with metal deficiency defect in its crystal is $N{i}_{0.98}O$. The crystal contains  ions. The fraction of nickel existing as $N{i}^{2+}$ ions in the crystal is-

1. 0.96

2. 0.04

3. 0.50

4. 0.31

Subtopic:  Density & Packing Fraction |
75%
From NCERT
NEET - 2019
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A metal has a fcc lattice. The edge length of the unit cell is 404 pm. The density of the metal is 2.72 g cm–3. The molar mass of the metal is:
(NA Avogadro's constant = 6.02 × 1023 mol–1)
1. 30 g mol–1
2. 27 g mol–1
3. 20 g mol–1
4. 40 g mol–1
Subtopic:  Density & Packing Fraction |
74%
From NCERT
AIPMT - 2013
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The anions (A) form hexagonal closest packing and atoms (C) occupy only 2/3 of octahedral voids in it. The general formula of the compound is-
1. CA
2. CA2
3. C2A3
4. C3A2

Subtopic:  Density & Packing Fraction |
74%
From NCERT
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A metal crystallizes with a fcc lattice. The edge of the unit cell is 408 pm. The diameter of the metal atom is:

1. 288 pm

2. 408 pm

3. 144 pm

4. 204 pm

Subtopic:  Density & Packing Fraction |
73%
From NCERT
AIPMT - 2012
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A solid has a bcc structure. If the distance of closest approach between the two atoms is 1.73 Å, then the edge length of the cell is:

1. 200 pm

2. $\sqrt{3}}{\sqrt{2}}$ pm

3. 142.2 pm

4. pm

Subtopic:  Density & Packing Fraction |
65%
From NCERT
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Copper crystallizes into an fcc lattice with an edge length of 3.61 × 10−8 cm. The density of copper crystal will be -

1. 7.46 g cm-3

2. 9.67 g cm-3

3. 8.96 g cm-3

4. 5.63 g cm-3

Subtopic:  Density & Packing Fraction |
50%
From NCERT
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Niobium crystallizes in body-centred cubic structure. If the density is 8.55 g cm−3, the atomic radius of niobium (atomic mass 93 u) is -

1. 13.32 nm

2. 12.32 nm

3. 14.32 nm

4. 15.32 nm

Subtopic:  Density & Packing Fraction |
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