An element has a body-centered cubic (BCC) structure with a cell edge of 288 pm. The atomic radius is:
1. pm
2. pm
3. pm
4. pm
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. |
The crystal with a metal deficiency defect is -
1. NaCl
2. FeO
3. ZnO
4. KCl
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
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
ln NaCl, the chloride ions occupy the space in a Fashion of
1. BCC
2. FCC
3. Both
4. None of the above
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
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 )
1. 2.0 g/cc
2. 2.66 g/cc
3. 3.06 g/cc
4. None of the above.
An element occurring in the bcc structure has unit cells. The total number of atoms of the element in these cells will be:
1.
2.
3.
4.
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.