explain how you will calculate the number of particles and number of unit cell in x g of metal
Answers
Explanation:
The arrangement of the unit cells will define the structure as well as the symmetry of the crystalline solids. Now a lattice point in the unit cell is generally where we would find a constituent particle. But it must be kept in mind that a lattice point can also be vacant.
Now, we must calculate the number of particles that are present in unit cells. For this let us first consider some general characteristics of unit cells and their structure. The contribution of atoms present at different lattice sites
A particle (atom, molecule or ion) which is located at the corners of the lattice, is shared by eight unit cells all in all. Hence the contribution of an atom at the corner to a particular unit cell is one-eighth
An atom on the face of the unit cell is shared by two unit cells. Hence the contribution of a particle at the face to a unit cell is 1/2
The constituent particle at the edge center is shared by four unit cells in the lattice. Hence its contribution to any one particular unit cell is one-fourth
An atom at the body center of a unit cell belongs entirely and only to that unit cell of the lattice. There is no sharing involved
So now let us calculate how many constituent particles are in all the different times of unit cells