[Avogadro constant ≅ 6 × 1023 mol–1, π ≅ 3]
[Atomic Mass of Cu = 63.55 u]
(i) Remove all the anions (X) except the central one
(ii) Replace all the face centered cations (M) by anions (X)
(iii) Remove all the corner cations (M)
(iv) Replace the central anion (X) with cation (M)
The value of in Z is ____.
metal (NA = 6.02 × 1023 mol–1)
If the unit cell of a mineral has cubic close packed (ccp) array of oxygen atoms with m fraction of octahedral holes occupied by aluminium ions and n fraction of tetrahedral holes occupied by magnesium ions, m and n, respectively, are
The arrangement of X− ions around A+ ion in solid AX is given in the figure (not drawn to scale). If the radius of X− is 250 pm, the radius of A+ is
Assertion Semiconductors are solids with conductivites in the intermediate range from 10−6 − 104 ohm−1 m−1.
Reason Intermediate conductivity in semiconductor is due to partially filled valence band.
A metal has a fcc lattice. The edge length of the unit cell is 404 pm. The density of the metal is 2.72 g cm−3. The molar mass of the metal is:
(NA Avogadro’s constant = 6.02 × 1023 mol−1)
Reason : Anion-anion contact is retained in LiCl structure because anions constitute the lattice.
The packing efficiency of the two-dimensional square unit cell shown below is
(Assume all circles are of the same radius)
STATEMENT-1: Band gap in germanium is small.
STATEMENT-2: The energy spread of each germanium atomic energy level is infinitesimally small.
|Column I||Column II|
|(A)||Simple cubic and face-centred cubic||(p)||have these cell parameters a = b = c and α = β = γ|
|(B)||Cubic and rhombohedral||(q)||are two crystal systems|
|(C)||Cubic and tetragonal||(r)||have only two crystallography angles of 90o|
|(D)||Hexagonal and monoclinic||(s)||belong to the same crystal system|
(D) Composition cannot be specified.
In any ionic solid (MX) with Schottky defects, the number of positive and negative ions are same.
Equal numbers of cation and anion vacancies are present.
(a) If both assertion and reason are CORRECT, and reason is the CORRECT explanation of the assertion.
(b) If both assertion and reason are CORRECT, but reason is NOT the CORRECT explanation of the assertion.
(c) If assertion is CORRECT, but reason is INCORRECT.
(d) If assertion is INCORRECT, but reason is CORRECT.