Question

Due to the Schottky effect, the density of a crystal ________.

Answer 1

Hint: Schottky defect is related to the lattice arrangement in the solid state. In this arrangement equal numbers of cations are missing from the lattice.

Complete step by step answer:
- Firstly, let us discuss the Schottky defect and Frenkel defect. These both defects are found in crystals i.e. ionic and non-ionic crystals.
- Second, in crystals when oppositely charged ions i.e. cations and anions are missing from the lattice sites, vacancies are formed and leads to the defect in the lattice.
- Now, if the cations and anions are missing in the lattice, the overall mass of the lattice decreases in case of schottky defect, but if we talk about the frenkel defect, the mass remains the same.
- The volume of the lattice remains the same.
- We know, Density= $\dfrac{Mass}{Volume}$, from the formula we can say that density is directly proportional to the mass. The decrease in the mass of lattice, density of the crystal decreases.
- Therefore, the missing vacancies lead to the lowering of the density.
- Due to the schottky defect, the density of crystal decreases.

Additional information: This defect is named after Walter H. Schottky. In the ionic crystals, vacancies are formed to maintain the overall neutral charge of the lattice. These vacancies are free to move in their entities.

Note: Don’t be confused between the types of crystals and the lattice arrangement. This defect is based on the basic formula of density relating it to the mass of the lattice. There are two types of defects: schottky and frenkel defect, so don’t get confused in between the both, they both defect differ from each other.