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WorksheetsCrystal structure and defect
Total questions: 40
Worksheet time: 19mins
What is a crystal?
A pure material that can’t be changed.
Material with a regular,repeating arrangement of atoms.
A foggy like material.
Which crystal structure does the picture show?
BBC (British Broadcasting Company)
FCC (Face-Centered Cubic)
SC (Simple Cubic)
BCC (Body Center Cubic)
Which crystal structure does the picture show?
BBC (British Broadcasting Company)
BCC (Body Center Cubic)
SC (Simple Cubic)
FCC (Face-Centered Cubic)
Which is NOT an example of a crystal found in nature
rock salt
diamonds
snowflakes
cataracts
leaves
Which of the following is a way that crystals can form in nature?
When liquids cool and start to harden.
When magma cools.
When water evaporates from a mixture.
All of the above.
Crystal system characterized by a ≠ b≠ c and α = β = γ = 90o
Hexagonal
Ortho rhombic
Tetragonal
Triclinic
Smallest repeating unit of crystal lattice
Lattice site
Unit cell
Crystal lattice
Lattice point
In a primitive unit cell atoms are present at the
Corners & Centers of any 2 opposite sides
Corners only
Corners and Body Centre
Corners & Centers of all faces
There are ……….. Bravais lattices corresponding to 7 different Crystal Systems
8
9
14
13
Number of atoms per unit cell in a Face Centered Cubic lattice
4
1
2
6
Example for crystalline solid
Glass
Quartz
Plastic
Rubber
Crystalline solids are
Isotropic
Allotropic
Anisotropic
Isomorphic
Defect shown by ionic crystals with large difference in size
Schottky Defect
Impurity Defect
Frenkel Defect
Metal Deficiency Defect
Defect causing decrease in density
Schottky
Frenkel
F- centre
Metal Excess
A semiconductor material
Ga
As
Ge
Al
AB AB … type close packing pattern represents
HCP
FCC
CCP
BCC
A defect where atoms occupy the empty space between existing atoms within a crystal
point defect
substitutional
interfacial
interstitial
A defect where new atoms replace existing atoms within a crystal
point defect
substitutional
interfacial
interstitial
Regions within a crystal where planes of atoms can slide past one another.
slip plane
point defect
grain boundary
interfacial
The boarder where two crystal grains meet.
slip plane
point defect
grain boundary
interfacial
Regions in crystals where atoms are not perfectly aligned due to an extra partial plane.
dislocation
interstitial
grain boundary
interfacial
The more loosely packed particles are, the more workable they are.
True
False
The unit cell with the most slip planes is _______.
FCC
BCC
HCP
Simple Cubic
The correct order of the packing efficiency in different types of unit cells is _______?
fcc < bcc < simple cubic
fcc > bcc > simple cubic
fcc < bcc > simple cubic
bcc < fcc > simple cubic
Which of the following statements about lattices and unit cells is correct?
A unit cell contains a whole number of complete molecules
Lattice points are chosen to lie on atoms.
Lattice points all have identical surroundings
Unit cells are constructed by connecting adjacent lattice points to give the largest possible repeat unit.
Consider the Bragg equation. If the value of the wavelength is doubled, which of the following is NOT true?
Bragg angles of reflections increase.
The d spacings become smaller.
The diffraction pattern expands.
Some previously accessible reflections can no longer be measured.
Atomic packing factor is
Distance between two adjacent atoms
Projected area fraction of atoms on a plane
Volume fraction of atoms in cell
None
Co-ordination no. & Atomic Packing Fraction of HCP structure is same as that of the -----------
SC
BCC
FCC
BCT
Which unit cell has eight particles located in the corners, has sides that are all the same length, and has angles of only 90?
body-centered cubic unit cell
triclinic unit cell
face-centered cubic unit cell
simple cubic unit cell
What is the common direction between the (132) and (133) planes?
[3 1 0]
[3 10]
[4 1 0]
[0 1 4]
Choose the characteristic that is not represent solid.
Regular and repeating arrangement of components.
Disordered structure
Have a sharp melting point
Example of solid is salt, sugar, diamond
Identify the number of particle in a unit cell and coordination number for Face Centered Cubic.
2:8
6:12
4:12
1:8
Define Schottky defect.
When an atom occupies a definite position in the lattice that is not normally occupied in the perfect crystal.
An atom is missing from its regular atomic site.
An ion displaced from a regular site to an interstitial site in ionic crystal.
A pair of one cation and one anion missing from regular sites in ionic crystal.
How does an ionic bond form?
One atom gives an electron to another atom
Atoms share electrons
The electrons form a "sea of electrons"
How does a covalent bond form?
One atom gives an electron to another atom
Atoms share electrons
The electrons form a "sea of electrons"
Which the following defects can be classified as point defect?
Vacancies
Substitutional atoms
Dislocations
Interstitial atoms
Grain boundaries
Choose the correct option(s).
APF of BCC is 0.64
APF of HCP is 0.76
APF of SC is 0.58
FCC is the cubic closed pack structure
