Advertisements
Advertisements
प्रश्न
Answer the following in brief.
Calculate the number of atoms in fcc unit cell.
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 `xx 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 `xx 1/2` atom per unit cell = 3
Therefore, fcc unit cell has one corner particle plus 3 face particles, making total of 4 particles per unit cell.
APPEARS IN
संबंधित प्रश्न
Obtain the relationship between the density of a substance and the edge length of the 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?
Find the number of atoms in the fcc unit cell.
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.
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?
In bcc unit cell, the edge length (a) and radius of sphere (r) are related to each other by equation:
How many total constituent particles are present in simple cubic unit cell?
The percentage of unoccupied volume in simple cubic cell is ______.
A metal crystallises in bcc unit cell with edge length 'a'. What will be the volume of one atom?
Sodium crystallizes in bcc structure with radius 1.86 × 10−8 cm. What is the length of unit cell of sodium?
An element crystallizes bcc type of unit cell, the density and edge length of unit cell is 4 g cm−3 and 500 pm respectively. What is the atomic mass of an element?
Copper and silver have ____________ crystal structure.
A metallic element has a cubic lattice with edge length of unit cell 2 Å. Calculate the number of unit cells in 200 g of the metal, if density of metal is 2.5 g cm-3?
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]
An element has a bee structure with unit cell edge length of 288 pm. How many unit cells and number of atoms are present in 200 g of the element?
Calculate the density of metal with molar mass 56 g mol- 1 that crystallises to form a bcc structure with edge length 288 pm.
At room temperature, polonium Crystallises in a primitive cubic unit cell. If a = 3.36 Å. Calculate the theoretical density of polonium. [It's atomic weight is 209 g/mol.]
What would be the empirical formula of a compound having a unit cell containing A ion shared equally at the corner of the cube and B ion on the centre of faces of the cube?
The number of particles present in Face Centred Cubic Unit cell is/are ______.
The cubic unit cell of a metal (molar mass = 63.55g mol−1) has an edge length of 362 pm. Its density is 8.92g cm−3.
The type of unit cell is ______.
