Properties of Solids
Intermolecular Forces of Attraction Ch. 11 is about liquids and solids… where the attraction between particles allows the formation of solids and liquids.
Four Solids – Overview •Molecular Solids (particles with IMF’s) •Covalent Network Solids (covalent bonding) •Ionic Solids (ionic bonding) •Metals (metallic bonding)
Molecular Solids Strong covalent forces within molecules Weak covalent forces between molecules Properties: Relatively soft Low melting points (<200°C) Poor conductors of heat or electricity
Molecular Solid Examples H2O - ice Dry Ice - CO2
Molecular Solid Examples Sugar crystals Extensive hydrogen bonding in ice holds the water molecules farther apart in a more ordered arrangement than in liquid water. The hexagonal symmetry of a snowflake reflects the structure of the ice crystal.
Covalent Network Solids Some covalent substances do not form discrete molecules Atoms are covalently bonded in large networks or chains by covalent bonds. Properties: Very hard Very high melting points
Covalent Network Solid Examples Diamond, C(s) All carbons connected by covalent bonds One of the strongest materials.
Covalent Network Solid Examples Graphite, C(s) Sheets of covalent networks of carbon weakly bonded to another sheet (used in pencils)
Covalent Network Solid Examples SiO2 (quartz, sand, glass)
Covalent Network Solid Examples Si (s)
Ionic Solids Attraction of positive and negative ions. Form crystalline structures. Properties: Hard and brittle High melting point Poor conductor of heat and electricity
Ionic Solids •A lattice of positive and negative ions
Metallic Solids Valence electrons are delocalized (freely floating) throughout the entire solid. “Sea of electrons” Form crystalline structures Properties: Excellent conductors of heat and electricity Malleable and ductile Varying hardness and melting points
Metals https://www.youtube.com/watch?v=vOuFTuvf4qk&feature=iv&src_vid=ZxWmyZmwXtA&annotation_id=annotation_2367300777
Metal Examples
Summary – Strength of Inter- and Intramolecular Forces •London Dispersion Force Dipole-Dipole Interactions Hydrogen Bonds Ion-Dipole Interactions Ionic Bonds (Ion-Ion) Covalent Bonds Covalent Network