Advertisements
Advertisements
प्रश्न
Find the number of atoms in the fcc unit cell.
Calculate the number of particles per unit cell in a face-centred cubic system.
In a face centred arrangement of atoms of an element, what will be the number of atoms present in respective unit cells?
Advertisements
उत्तर
A face-centred cubic (fcc) unit cell has particles at the eight corners plus particles at the centre of its six faces.
Each particle present at the corner of a given unit cell is shared with seven other neighbouring unit cells. As a result, its contribution to the given unit cell is only `1/8`.
Thus, the number of particles present at corners per unit cell
= 8 corner atoms × `1/8` atom per unit cell = 1
Each particle at the centre of the six faces is shared with one neighbouring cube. Thus, 1/2 of each face particle belongs to the given unit cell. Thus, the number of particles present at faces per unit cell
= 6 atoms at the faces × `1/2` atom per unit cell = 3
Therefore, fcc unit cell has one corner particle plus 3 face particles, making a total of 4 particles per unit cell.
APPEARS IN
संबंधित प्रश्न
Answer the following in brief.
Calculate the number of atoms in fcc unit cell.
Give the percentage of empty space in bcc lattice.
If the total volume of a simple cubic unit cell is 6.817 × 10-23 cm3, what is the volume occupied by particles in the unit cell?
Calculate the number of unit cells in 0.3 g of a species having density of 8.5 g/cm3 and unit cell edge length 3.25 × 10-8 cm.
Derive the relationship between density of substance, its molar mass, and the unit cell edge length. Explain how you will calculate the number of particles, and a number of unit cells in x g of metal.
Silver crystallises in fcc structure, if edge length of unit cell is 316.5 pm. What is the radius of silver atom?
An element crystallizes in fcc type of unit cell. The volume of one unit cell is 24.99 × 10-24 cm3 and density of the element 7.2 g cm-3, Calculate the number of unit cells in 36 g of pure sample of element?
What is the percentage of unoccupied space in fcc unit cell?
An element (atomic mass M g/mol) having bcc structure has unit cell edge 400 pm. The density of the element is ____________ g/cm3.
[NA = 6.0 × 1023 atom mol−1)
How many total constituent particles are present in simple cubic unit cell?
A metal crystallises in bcc unit cell with edge length 'a'. What will be the volume of one atom?
If the edge of a body-centred unit cell is 360 pm, what will be the approximate radius of the atom present in it? (in pm)
Sodium crystallizes in bcc structure with radius 1.86 × 10−8 cm. What is the length of unit cell of sodium?
Copper and silver have ____________ crystal structure.
Which of the following formulae is used to find edge length of bee unit cell?
What is the density of iron crystal which crystallizes in body-centred cubic structure with edge length 287 pm? (At. mass of Fe = 56 amu)
The number of atoms in 100 g of an fcc crystal with density 10 g cm-3 and unit cell edge length 200 pm is equal to ______.
The coordination number of atoms in body-centred cubic structure (bcc) is ______.
Gold crystallises into face-centred cubic cells. The edge length of a unit cell is 4.08 × 10–8 cm. Calculate the density of gold. [Molar mass of gold = 197 g mol–1]
In face centred cubic unit cell, what is the volume occupied?
Identify unit cell from following having four particles in it
The total number of different primitive unit cells is ______.
An element crystallises in fee structure. If molar mass of element is 72.7 g mol -1, the mass of its one unit cell will be ______.
Which of the following metals exhibits minimum packing efficiency in its cubic system?
