Properties of Solids PDF
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This document provides notes on the properties of solids, focusing on the differences between crystalline and amorphous solids. It discusses the types of solids, their structures, and the properties that define them. These notes are suited for secondary school-level chemistry students.
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Properties of Solids Types of solids 1. Amorphous Solids -does not always adapt the same form. components of amorphous solids are not arranged in regular arrays. Its constituent particles are randomly arranged. Ex. Asphalt, rubber, glass, plastic, Silicon(used in solar cells a...
Properties of Solids Types of solids 1. Amorphous Solids -does not always adapt the same form. components of amorphous solids are not arranged in regular arrays. Its constituent particles are randomly arranged. Ex. Asphalt, rubber, glass, plastic, Silicon(used in solar cells and thin films) and quartz glass. -They are a result of the melting or solidifying of liquids before the molecules can achieve internal order. Do not have sharp melting points, instead they soften first and melt little by littleover a wide range of temperature. Example : Examples: Obsidian, a volcanic glass with the same chemical composition as granite (typically KAlSi3O8), tends to have curved, irregular surfaces when cleaved. - Coal and charcoal are also classified as amorphous. 2. Crystalline solids- well defined crystal lattice. -they can form a regular repeating three- dimensional structure called a crystal lattice. Lattice –a three dimensional system of points designating the positions of components (atoms, ions or molecules) that make up a system. Unit cell- the smallest repeating unit of a lattice. Seven common unit cells of a lattice. Crystalline faces. The faces of crystals can intersect at right angles, as in galena (PbS) and pyrite (FeS2), or at other angles, as in quartz. The lattice of crystalline quartz (SiO2). The atoms form a regular arrangement in a structure that consists of linked tetrahedral. Classification of Crystalline Solids Type Components Typs of Typical Properties Examples that occupy Interaction the Lattice between points components of Lattice Ionic Solids Ions (cations Ionic bond/ Hard, High melting point, NaCl, CaF2 , KNO3, and anions) coulombic forces nonconductor as a solid but CaCO3, CaCl2 electrical conductor when dissolved/melted. Molecular Discrete Hydrogen Soft, low melting points, maybe H2O, SO2, NH3, Solids molecules(pola bond/Dipole-dipole brittle, nonconductors C12H22O11(sugar), dry r or nonpolar) forces/or London ice (Solid CO2, CH2Cl2 dispersion forces Metallic Solids Metal atoms Delocalized covalent Low melting point and soft, high Na, Fe, Ag, Au, brass, bond melting point and hard, steel, bronze, Cu, malleable, brittle, good heat and alloys electrical conductor Network Nonmetal Direction covalent Very high melting points, Hard Diamond, SiO2 (silica), Solids Atoms bond(leading to giant SiC(Carborundum), molecules) Al2O3(alundum),graphi te Group 8A Group 8A London dispersion Very low melting points Argon, Krypton solids (noble gases) forces
