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Download 12th-class solid state important topics part 1 and more Study notes Chemistry in PDF only on Docsity!
Solid State Matter ¢ Matter is anything that has mass and occupies space. Types of Matter 1. Solid 2. Liquid 3. Gas Solid e Solid is a physical form of matter. State e State is a medium in which matter exists. e All three states are interconvertible; it depends on temperature and pressure conditions. (Transition Diagram) Solid © Liquid © Gas Characteristics of Solids 1. Solids have definite shape, volume, and density. 2. Solids are denser than liquid. 3. Solids are hard, rigid, and highly incompressible as their short intermolecular distance between the atoms. lsomorphism lsomorphism is a phenomenon where two or more crystalline substances have the same crystal structure and similar chemical properties. E.g., NaNO, and CaCQ3 . Amorphous Solids 1. Amorphous Solids Amorphous solids lack a definite, regular arrangement of particles and are often described as supercooled liquids or pseudo solids. They do not possess sharp melting points, instead softening gradually over a range of temperatures. ¢ 2. lsotropy Amorphous solids are isotropic, meaning their physical properties are the same in all directions. ¢ 3. Examples Examples of amorphous solids include glass and sugar. ¢@ 6. It is obtained by rapid cooling. 7. The outer surface is made up of irregular surfaces. (e.g., glass) 3. Solids formed by aggregation of molecules 1. Molecular solids: There are intermolecular solids formed by aggregation of molecules. This depends on the formation of molecules involved in intermolecular attraction. 2. Polar molecular solids: There are polar molecular solids having dipole-dipole forces of attraction. Example: HCI. 3. Non-polar molecular solids: There are non-polar molecular solids having London dispersion forces. Example: Cl2. 4. Hydrogen bonding molecular solids: It is formed by hydrogen atom of one molecule & electronegative atom. lonic solid lonic solids are formed by the molecules which contain a positive and negative changes. Smaller cation and larger anions. The molecule is neutral because the ion balances each other. There is a force of attraction between ions of opposite charge and force of repulsion between ions of same charges. Due to opposite charges, ionic solids have a 3-dimensional structure. They are hard and brittle. They have high melting point. They do not conduct electricity in solid state. Metallic solids Metallic solids are formed between metal atom of same element. There is a force of attraction between positively charge metal ion and negatively charge delocalized electrons. Good conductors of heat and electricity. Good conductors of electricity have mobile electrons. High melting point. In layer structure, one layer slides over another, hence they show malleability and ductility property. e Unit cell Unit cell is the smallest repeating unit in the crystal lattice. ¢ Lattice Point Any point of intersection of lines in the crystal is called lattice point. ¢ Space lattice The collection of all the points in the crystal having the same environment is called space lattice. e Lattice Lattice is the structure which is made up of strips which one diagonally cross other. e¢ Type of crystal lattice Simple cubic lattice (SCC) In simple cubic lattice particle is present at each corner. Share in all 8 corners. No of particles (Z) = 1/8 * 8 = 1 Each corner cubic lattice (FCC) each corner particle is one particle in a unit cell No. of particle (1) = 8 x (1/8) = 1 Face centre cubic lattice (FCC) In FCC, 1 particle is present at each corner and 6 particle at each face. Each face share with 1/2 neighbouring faces. No. of particle (2) = 6 x (1/2) = 3 Total =1+3= 4 Page 2 (Right): Type of Defect 1. Vacancy or Schottky defect: During its crystallization, if some of the constituent particles leave their original lattice site and create vacant sites, then the defect is called vacancy defect. In ionic solids, if equal no. of cations and anions are found to be missing from their lattice sites, then the defect is called Schottky defect. It leads to the decrease in density of the substance. E.g., NaCl, KCI, AgBr. Vacant sites or holes (Diagram of lattice with vacant sites) Vacancy 
