physical properties

• What are the four key types of solid structures?

  Ionic, Metallic, Giant covalent, Molecular
• What forms ionic structures?

  Compounds of metals with non-metals
• Give an example of an ionic compound.

  Sodium chloride (NaCl)
• What is a common example of a metallic structure?

  Magnesium
• What characterizes giant covalent structures?

  Strong covalent bonds throughout the structure
• Name a giant covalent structure.

  Diamond
• What is a property of molecular solids?

  They have very weak intermolecular forces
• What is the melting point characteristic of ionic crystals?

  They have high melting points
• Why can't ionic crystals conduct electricity as solids?

  The ions are fixed in place
• How do ionic compounds behave in polar solvents?

  They are soluble and dissociate into ions
• What happens to ionic compounds in solution?

  The ions become mobile and conduct electricity
• What is a property of giant covalent crystals regarding solubility?

  They do not dissolve in anything
• What allows metals to conduct electricity?

  The presence of free electrons
• What is the melting point characteristic of metals?

  They have high melting points
• How does the number of free electrons affect a metal's melting point?

  More free electrons lead to higher melting points
• Why do metals not generally dissolve in water?

  Many react with water to form hydroxides
• What characterizes molecular solids at room temperature?

  They often have low melting points
• What is an example of a molecular solid?

  Ice
• How do molecular solids behave in terms of conductivity?

  They do not conduct electricity
• What distinguishes molecular solids from covalent structures?

  Molecular solids are held by intermolecular forces
• What happens when a molecular solid melts or boils?

  Intermolecular forces are broken, not covalent bonds
• What is the nature of forces in giant covalent solids?

  Only intramolecular forces are present
• Why do giant covalent structures have higher melting points?

  Covalent bonds must be broken to melt
• What are the properties of ionic crystals?

  • Strong electrostatic attractions between ions
  • High melting points
  • Cannot conduct electricity as solids
  • Soluble in polar solvents
  • Conduct electricity in solution
• What are the properties of giant covalent crystals?

  • Strong covalent bonds throughout
  • High melting and boiling points
  • Sublime directly to gas
  • Insoluble in any solvent
• What are the properties of metals?

  • Sea of free electrons
  • High melting points
  • Conduct electricity as solids and liquids
  • Generally do not dissolve in water
• What are the properties of molecular solids?

  • Very weak intermolecular forces
  • Low melting points
  • Often liquids or gases at room temperature
  • Do not conduct electricity
  • Some may dissolve in water
• What is the difference between molecular solids and giant covalent structures?

  • Molecular solids: held by intermolecular forces
  • Giant covalent: one molecule with intramolecular forces
  • Intramolecular forces are stronger than intermolecular forces