Chemistry 2 Marks Questions

This defect is created in the crystal when the same number of cations and anions are missing from their positions and thus holes (called cation vacancy or anion vacancy) are produced. Since the number of cations and anions that are left in the crystal even after the missing of cations and anions is the same, the crystal remains electrically neutral. The production of two holes, one due to the missing of a cation and the other due to the missing of an anion. Examples of ionic crystals having Schottky defect are NaCl, KCI, KBr, CsCl etc.

Covalent or Network Solids: In this type of solids the constituent particles are atoms of same or different elements connected to each other by covalent bond network. The atoms interlocked by a network of covalent bonds produce a crystal which is considered to be a single giant molecule. Example of covalent solid is Diamond.

Point defects are imperfections in the structure of a material at specific points within its lattice. These defects can arise due to missing atoms (vacancies), extra atoms (interstitials), or atoms occupying irregular positions (substitutional defects). They influence material's properties such as electrical conductivity and mechanical strength.