# Lithium metal crystallizes in a body-centered cubic crystal. If the length of the side of the unit cell of lithium is 351 pm, the atomic radius of the lithium will be: 1. 240.8 pm 2. 151.8 pm 3. 75.5 pm 4. 300.5 pm

Subtopic:  Introduction & Crystal System |
84%
From NCERT
AIPMT - 2009
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If 'a’ stands for the edge length of the cubic systems: simple cubic, body-centered cubic, and face-centered cubic, then the ratio of radii of the spheres in these systems will be respectively:

1. $\frac{1}{2}\mathrm{a :}$ $\frac{\sqrt{3}}{4}\mathrm{a}$ $:$ $\frac{1}{2\sqrt{2}}\mathrm{a}$

2. $\frac{1}{2}\mathrm{a :}$ $\sqrt{3}\mathrm{a}$ $:$ $\frac{1}{\sqrt{2}}\mathrm{a}$

3. $\frac{1}{2}\mathrm{a :}$ $\frac{\sqrt{3}}{2}\mathrm{a}$ $:$ $\frac{\sqrt{2}}{2}\mathrm{a}$

4. $1\mathrm{a :}$ $\sqrt{3}\mathrm{a}$ $:$ $\sqrt{2}\mathrm{a}$

Subtopic:  Voids, Radius Ratio & Coordination Number |
86%
From NCERT
AIPMT - 2008
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The percentage of free space in a body-centered cubic unit cell is:

1. 30%
2. 32%
3. 34%
4. 28%
Subtopic:  Density & Packing Fraction |
87%
From NCERT
AIPMT - 2008
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Silicon gives p-type of semiconductor on doping with:

1. Germanium.

2. Arsenic.

3. Selenium.

4. Boron.

Subtopic:  Imperfections in Solids & Semiconductors |
72%
From NCERT
AIPMT - 2008
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The fraction of total volume occupied by the atoms present in a simple cube is:

1. $\frac{\mathrm{\pi }}{6}$

2. $\frac{\mathrm{\pi }}{3\sqrt{2}}$

3. $\frac{\mathrm{\pi }}{4\sqrt{2}}$

4. $\frac{\mathrm{\pi }}{4}$

Subtopic:  Density & Packing Fraction |
81%
From NCERT
AIPMT - 2007
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CsBr crystallises in a body-centered cubic lattice. The unit cell length is 436.6 pm. Given that the atomic mass of Cs = 133 amu and that of Br = 80 amu and the Avogadro number being 6.02×1023 mol-1, the density of CsBr is:

1. 42.5 $g/c{m}^{3}$

2. 0.425 $g/c{m}^{3}$

3. 8.25 $g/c{m}^{3}$

4. 4.25 $g/c{m}^{3}$

Subtopic:  Introduction & Crystal System |
From NCERT
AIPMT - 2006
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The appearance of colour in solid alkali metal halides is generally due to:

1. F-centres.

2. Schottky defect.

3. Frenkel defect.

4. Interstitial positions.

Subtopic:  Imperfections in Solids & Semiconductors |
80%
From NCERT
AIPMT - 2006
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A compound is formed by cation C and anion A. The anions form hexagonal close packed (hcp) lattice and the cations occupy 75 % of octahedral voids. The formula of the compound is:

1. ${\mathrm{C}}_{3}{\mathrm{A}}_{4}$

2. ${\mathrm{C}}_{2}{\mathrm{A}}_{3}$

3. ${\mathrm{C}}_{3}{\mathrm{A}}_{2}$

4. ${\mathrm{C}}_{4}{\mathrm{A}}_{3}$

Subtopic:  Voids, Radius Ratio & Coordination Number |
51%
From NCERT
NEET - 2019
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If the lattice parameter for a crystalline structure is 3.6 Å, then the atomic radius in fcc crystal is:

1. 1.81 Å

2. 2.10 Å

3. 2.92 Å

4. 1.27 Å

Subtopic:  Density & Packing Fraction |
75%
From NCERT
AIPMT - 2008
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Copper crystallizes in a face-centered cubic lattice with a unit cell length of 361 pm. The radius of the copper atom is:

1. 128 pm

2. 157 pm

3. 181 pm

4. 108 pm

Subtopic:  Voids, Radius Ratio & Coordination Number |
78%
From NCERT
AIPMT - 2009
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