From the fact that the length of the side of a unit cell of lithium is 351 pm. Calculate its

atomic radius. Lithium forms body-centered cubic crystals.

(1) 152.69 pm

(2) 62.71 pm

(3) 151.98 pm

(4) 54.61 pm

Atomic radius of silver is 144.5 pm. The unit cell of silver is a face centred cube. Calculate the density of silver.

(1) 10.50 g/cm³

(2) 16.50 g/cm³

(3) 12.30 g/cm³

(4) 15.50 g/cm³

A metallic element exists as a cubic lattice. Each edge of the unit cell is 2.88 Å. The density of the metal is 7.20 g cm^–3.  The number of unit cells, that will be present in 100 gm of the metal is: 

1. 5.82 × 10²³

2. 16.33 × 10²³

3. 7.49 × 10²⁴

4. 6.9 × 10²⁴

Silver crystallizes in a face centred cubic system, 0.408 nm along each edge. The density of silver is 10.6 $g/c{m}^3$ and the atomic mass is 107.9 g/mol. Calculate Avogadro's number.

(1) $6.00\times {10}^{23}$ atom/mol

(2) $9.31\times {10}^{23}$ atom/mol

(3) $6.23\times {10}^{23}$ atom/mol

(4) $9.61\times {10}^{23}$atom/mol

Fraction of total volume occupied by atoms in a simple cube is

(1) $\frac{\pi }{2}$

(2) $\frac{\sqrt{3}\pi }{8}$

(3) $\frac{\sqrt{2}\pi }{6}$

(4) $\frac{\pi }{6}$

A solid AB has the NaCl structure. If radius of cation A⁺ is 120 pm, calculate the maximum possible value of the radius of the anion B^–

(1) 240 pm

(2) 280 pm

(3) 270 pm

(4) 290 pm

CsBr has a (bcc) arrangement and its unit cell edge length is 400 pm. Calculate the interionic distance in CsBr.

(1) 346.4 pm

(2) 643 pm

(3) 66.31 pm

(4) 431.5 pm

The first order reflection (n = 1) from a crystal of the X-ray from a copper anode tube $(\lambda =0.154nm)$ occurs at an angle of 16.3°. What is the distance between the set of planes causing the diffraction.

(1) $0.374nm$

(2) $0.561nm$

(3) $0.274nm$ 

(4) $0.395nm$

The diffraction of barium with X-radiation of wavelength 2.29Å gives a first – order reflection at 30°. What is the distance between the diffracted planes.

(1) 3.29 Å

(2) 4.39 Å

(3) 2.29 Å

(4) 6.29 Å

When an electron in an excited Mo atom falls from L to the K shell, an X-ray is emitted. These X-rays are diffracted at angle of $7{.75}^o$ by planes with a separation of 2.64Å. What is the difference in energy between K-shell and L-shell in Mo assuming a first-order diffraction. $(\sin 7{.75}^o=0.1349)$

(1) 36.88 $\times {10}^{-15}J$

(2) $27.88\times {10}^{-16}J$

(3) 63.88 $\times {10}^{-17}J$

(4) $64.88\times {10}^{-16}J$