A compound is formed by two elements A and B. The element B forms cubic close-packed structure and atoms of A occupy 1/3 of tetrahedral voids. If the formula of the compound is $$A_x B_y$$ then the value of x+y is in option
1.  2
2.  5
3.  4
4.  3
Subtopic:  Density & Packing Fraction |
54%
From NCERT
NEET - 2023
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How are edge length 'a' of the unit cell and radius 'r' of the sphere related to each other in ccp structure?
 1 $$a = 2r$$ 2 $$a = r /2\sqrt2$$ 3 $$a = 4r /\sqrt3$$ 4 $$a = 2\sqrt2r$$
Subtopic:  Density & Packing Fraction |
From NCERT
NEET - 2023
Hints

Copper crystallises in fcc unit cell with a cell edge length of $$3.608 \times 10^{-8}$$ cm. The density of copper is $$8.92 \ g ~cm^{-3}$$. The atomic mass of copper is:

1. 65 u
2. 63.1 u
3. 31.55 u
4. 60 u
Subtopic:  Density & Packing Fraction |
69%
From NCERT
NEET - 2022
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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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