The force that binds a metal ion to a number of electrons within its sphere of influence is known as
Covalent bond
Ionic bond
Coordinate bond
Metallic bond
Which of the following has its atoms connected by valence bonds?
sodium chloride
diamond
graphite
none of the above
In ______________ crystals, the units occupying lattice are positive and negative ions.
Metallic
Covalent
Ionic
Molecular
Which crystal does not have free electrons for electric conduction?
ionic crystal
covalent network crystal
both (a) and (b)
Which unit cell have diamond cell?
triclinic
trigonal
octahedral
tetrahedral
______________ defects appears generally in ionic crystal in which the positive and negative ions donot differ much in size.
Point
Frenkel
Schottky
Metal excess
_____________ solids have definite and ordered arrangement of the constituents extended over a long range order.
Amorphous
Crystalline
Isomeric
The Braggs equation is
a = 2dsinΘ
nd= 2aSinΘ
2a = nd sinΘ
nλ = 2d sinΘ
At what temperature does the carbon atom in diamond splits?
40oC
4000oC
400oC
40000oC
At what temperature diamond can be vapourized?
1000o C
7000oC