An element has a body-centered cubic (BCC) structure with a cell edge of 288 pm. The atomic radius is:

1. 24×288 pm

2. 43×288 pm

3. 42×288 pm

4. 34×288 pm

Subtopic:  Introduction & Crystal System | Density & Packing Fraction |
 81%
Level 1: 80%+
NEET - 2020
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Select the correct option based on statements below:

Assertion (A): Due to Frenkel defect, the density of the crystalline solid decreases.
Reason (R): In Frenkel defect cation and anion leave the crystal.
 
1. Both (A) and (R) are true and (R) is the correct explanation of (A).
2. Both (A) and (R) are true but (R) is not the correct explanation of (A).
3. (A) is true but (R) is false.
4. Both (A) and (R) are false.
Subtopic:  Imperfections in Solids & Semiconductors |
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Level 1: 80%+
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The crystal with a metal deficiency defect is - 

1. NaCl 

2. FeO

3. ZnO 

4. KCl

Subtopic:  Imperfections in Solids & Semiconductors |
 72%
Level 2: 60%+
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The radius ratio (r+/r-) of KF is 0.98. The structure of KF is similar to

1. NaCl

2. CsCl

3. ZnS

4. Both 1 and 2

Subtopic:  Voids, Radius Ratio & Coordination Number |
 63%
Level 2: 60%+
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A compound formed by elements A and B crystallizes in cubic structure where A atoms are at the corners or a cube and B atoms are at the face centre. The formula of the compound is :

1. AB

2. AB2

3. AB3

4. AB4

Subtopic:  Introduction & Crystal System |
 79%
Level 2: 60%+
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ln NaCl, the chloride ions occupy the space in a Fashion of 

1. BCC

2. FCC

3. Both 

4. None of the above 

Subtopic:  Introduction & Crystal System |
 71%
Level 2: 60%+
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A compound formed by elements A and B crystallizes in cubic structure where A atoms are at the corners or a cube and B atoms are at the face centre. The formula of the compound is :

(1) AB

(2) AB2

(3) AB3

(4) AB4

Subtopic:  Introduction & Crystal System |
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Level 1: 80%+
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If an element (at. Wt. = 50) crystallises in fcc lattice, with a = 0.50 nm, then the density of unit cell if it contains 0.25 % Schottky defect is -

(Use NA=6×1023

1. 2.0 g/cc

2. 2.66 g/cc

3. 3.06 g/cc

4. None of the above.

Subtopic:  Imperfections in Solids & Semiconductors |
 58%
Level 3: 35%-60%
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An element occurring in the bcc structure has 12.08×1023 unit cells. The total number of atoms of the element in these cells will be:

1. 24.16×1023

2. 36.18×1023

3. 6.04×1023

4. 12.08×1023

Subtopic:  Density & Packing Fraction |
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Level 2: 60%+
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NaCl sometimes appear yellow in colour because of :

1. Reaction with air.

2. Metal excess defect due to anionic vacancies.

3. Metal deficiency defect due to cation vacancies.

4. Schottky defect.

Subtopic:  Imperfections in Solids & Semiconductors |
 77%
Level 2: 60%+
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