Class 12th

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(i) Square close packing in two dimensions.

(a) Triangular voids 

(ii) Hexagonal close packing two dimensions. 

(b) Pattern of spheres is repeated in every fourth layer

(iii) Hexagonal close packing in three dimensions.

(c) Coordination number = 4 

(iv) Cubic close packing in three dimensions.

(d) Pattern of sphere is repeated in alternate layers

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(i) Mg in solid state

(a) p-Type semiconductor 

(ii) MgCl₂in molten state

(b) n-Type semiconductor 

(iii) Silicon with phosphorus

(c) Electrolytic conductors

(iv) Germanium with boron

(d) Electronic conductors

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(i) Impurity defect

(a) NaCl with anionic sites called F-centres

(ii) Metal excess defect

(b) FeO with Fe³⁺

(iii) Metal deficiency defect

(c) NaCl with Sr²⁺ and some cationic sites vacant

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(i) Primitive cubic unit cell

(a) Each of the three perpendicular edges compulsorily have the different edge length i.e., a≠b≠c.

(ii) Body centred cubic unit cell

(b) Number of atoms per unit cell is one.

(iii) Face centred cubic unit cell

(c) Each of the three perpendicular edges compulsorily have the same edge length i.e., a = b = c

(iv) End centred orthorhombic

(d) In addition to the contribution from the unit cell to the corner atoms, the number of atoms present in a unit cell is one.

(e) In addition to the contribution from the corner atoms the number of atoms present in a unit cell is three.

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(i) Simple vacancy defect

(a) shown by non-ionic solids and increases density of the solid.

(ii) Simple interstitial defect

(b) shown by ionic solids and decreases density of the solid.

(iii) Frenkel defect

(c) shown by non-ionic solids and density of the solid decreases

(iv) Schottky defect

(d) shown by ionic solids and density of the solid remains the same