A metallic elements exists as a cubic lattice. Each edge of the unit cell is 2.88Å. The density of the metal is 7.20 g cm–3. How many unit cells will be present in 100 gm of the metal.
(1) 5.82 × 1023
(2) 6.33 × 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 and the atomic mass is 107.9 g/mol. Calculate Avogadro's number.
Fraction of total volume occupied by atoms in a simple cube is
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
Concept Questions :-
CsBr has a (bcc) arrangement and its unit cell edge length is 400 pm. Calculate the interionic distance in CsCl [CBSE 1993]
(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 occurs at an angle of 16.3°. What is the distance between the set of planes causing the diffraction.
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 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.
Which is the incorrect statement?
(a) FeO0.98 has non-stoichiometric metal deficiency defect
(b) Density decreases in case of crystals with Schottky's defect
(c) NaCI(s) is insulator, silicon is semiconductor, silver is conductor, quartz is piezoelectric crystal
(d) Frenkel defect is favoured in those ionic compounds in which sizes of cation and anions are almost equal
Concept Questions :-
In calcium fluoride, having the fluorite structure, the coordination numbers for calcium ion (Ca2+) and fluoride ion (F-) are
(a) 4 and 2 (b) 6 and 6
(c) 8 and 4 (d) 4 and 8