Test: Types of Solids and Properties - JEE MCQ

In crystalline solid there is perfect arrangement of the constituent particles only at 0K. They have sharp M.P.

Glass is an amorphous solid.

There were atoms on the face-centres removing face-centred atoms along one of the
axes means removal of atoms.
Now, number of atoms per unit cell

Number of atoms per unit cell
Hence the resultant stoichiometry is

White tin, an allotropic form of tin is an example of tetragonal system and for tetragonal system, one side is not equal to other two while all the angles are equal, ie, a = b ≠ c and α = β = γ = 90^∘.
Hence, Assertion (A) is true but Reason (R) is not.

For FCC, number of X atoms = 4/unit cell
Number of Tetrahedral Voids = Z = 8
Number of Octahedral Voids = Y = 4
Number of atoms removed along one body diagonal = 2X (corner) and 2Z (TVs) and 1 Y (OV at body centre)
∴ Number of X atoms left
Number of Y atom left = 4 - (1 × 1) = 3
Number of Z atom left = 8 - (2 × 1) = 6
The simplest formula