Advertisements
Advertisements
Question
Answer the following in brief.
Calculate the number of atoms in fcc unit cell.
Advertisements
Solution
- 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
RELATED QUESTIONS
Obtain the relationship between the density of a substance and the edge length of the unit cell.
An element with molar mass 27 g/mol forms a cubic unit cell with edge length of 405 p.m. If the density of the element is 2.7 g/cm3, what is the nature of the cubic unit cell?
Write the relationship between radius of atom and edge length of fcc unit cell.
Give the percentage of empty space in bcc lattice.
Find the number of atoms in the fcc 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.
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?
How many total constituent particles are present in simple cubic unit cell?
The percentage of unoccupied volume in simple cubic cell is ______.
The number of atoms in 500 g of a fcc crystal of a metal with density d = 10 g/cm3 and cell edge 100 pm, is equal to ____________.
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?
Consider the following unit cell.
The number of particles (spheres) per unit cell is:
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 ______.
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?
An element with molar mass 2.7 × 10-2 kg/mol. Forms a cubic units cell with edge length of 405 pm. If the density is 2.7 × 103 kg/m3. Find the nature of a cubic unit cell.
The correct sequence of the atomic layers in cubic close packing is ______.
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 ______.
Which of the following metals exhibits minimum packing efficiency in its cubic system?
Calculate the molar mass of an element having density 2.8 g cm−3 and forms fcc unit cell.
[a3.NA = 38.5 cm3 mol−1]
Calculate the molar mass of an element having a density of 19.2 g cm−3 if it forms an fcc structure [a3 × NA = 40 cm3 mol−1].
