The Structure of Crystalline Solids

Question 1

material is one in which the atoms are situated in a repeating or
periodic array over large atomic distances—that is, long-range order exists

Answer 1

Crystalline

Question 2

the material, the manner in which atoms, ions, or molecules are spatially arranged.

Answer 2

Crystal structure

Question 3

constituent particles are not arranged in any regular fashion; they may be at the most some short range order

Answer 3

amorphous solid

Question 4

constituent particles are arranged in any regular fashion, containing short range order as well as long range order

Answer 4

Crystalline Solids

Question 5

is used in the context of crystal structures; means a three-dimensional array of points coinciding with atom positions (or sphere centres).

Answer 5

Lattice

Question 6

Three relatively simple crystal structures are found
for most of the common metals

Answer 6

1.) face-centered cubic (FCC) crystal structure

2.) body centered cubic (BCC) crystal structure

3.) hexagonal close-packed (HCP) crystal structure

Question 7

It contains 4 atoms in a unit cell. The atomic packing factor is
0.74 which means it has 26% void space per unit cell.

Answer 7

face-centered cubic (FCC) crystal structure

Question 8

Two other important characteristics of a crystal structure

Answer 8

Coordination number
Atomic packing factor (APF)

Question 9

For metals, each atom has the
same number of nearest-neighbour or touching atoms,

Answer 9

Coordination number

Question 10

is the sum of the sphere
volumes of all atoms within a unit cell (assuming the atomic
hard-sphere model) divided by the unit cell volume

Answer 10

Atomic packing factor (APF)

Question 11

The atomic packing factor is 0.68 which means it has 32%
void space per unit cell. Contain 2 atoms in a unit cell

Answer 11

BODY-CENTERED CUBIC (BCC)

Question 12

The equivalent of 6 atoms is contained in each unit cell; one-sixth of each of the 12 top and bottom face corner atoms, one-half of each of the 2 center face atoms, and all 3 midplane interior atoms. The atomic packing
factor for HCP is 0.74 which means it has 26% void space per unit cell.

Answer 12

HEXAGONAL-CLOSE PACKED (HCP)