Classify crystalline solids on the basis of nature of forces among the constituent particles.

Explanation

Based on the ·nature of forces among the constituent particles, crystalline solids are of four types These are as follows :
i) Ionic solids ii) Covalent solids iii) Metallic solids iv) Molecular solids
i) Ionic solids : In ionic solids, the constituent particles are ions. These ions of opposite charges are held together by electrostatic forces of attraction. NaCl, KF, `CuSO_4` etc., are the examples ofionic solids.
ii) Covalent solids : In covalent solids, the constituent particles are atoms. These atoms are held together by covalent bonds. Diamond, silicon carbide, quartz etc., are the examples of covalent solids.
iii) Metallic solids : In metallic solids, the constituent particles are positively charged kernels and mobile electrons. These are held together by electrical forces between the positively charged kernels and mobile electrons.These electrical forces are called metallic bonds Cu, Ag, Au, Fe, etc., are the examples of metallic solids.
iv) Molecular solids : In molecular solids, the constituent particles are small molecules. These molecules are held together by weak vander Waal.s forces of attraction. Solid carbon-dioxide, iodine, naphthalene etc., are the examples of molecular solids