Properties of Solids

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Properties of Solids
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Classifying Solids

• Solids can be classified according to
• Arrangement of particles
• Amorphous solids particles arrangements lack
  order (rubber glass)
• Crystalline solids with organized particle
  arrangements and as a result a distinct shape
• Bonds that hold them together (i.e. Ionic,
  covalent)

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Properties of Solids

• Properties of solids depend on the forces between
  particles
• 4 types of solids
• Ionic (cation and anion)
• Metallic (metals)
• Molecular (nonmetals)
• Covalent Network (metalloid/carbon)

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Ionic Crystals

• High melting point
• Hard, brittle
• High solubility in water
• Electrolytes (in solution)

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Metallic Crystals

• Positive nuclei surrounded by loosely held
  valence electrons (metals have low ionization
  energies)
• Creates a delocalized sea of valence electrons

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Metallic Crystals
Property Explanation
Crystalline Electrons act as electrostatic glue.
Hard dense Strong attraction between electron sea and positive nuclei.
Lustrous Valence electrons absorb and re-emit many wavelengths of light.
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Metallic Crystals
Property Explanation
Malleable, ductile Nondirectional bonds, atoms can slide over each other while remaining bonded.
Conducts electricity Free-floating valence electrons.
Conducts heat Sea of electrons
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Molecular Crystals

• Soft
• Low melting point
• Nonelectrolytes

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Covalent Network Crystals

• Very hard and brittle
• Very high melting points
• Nonelectrolytes

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Covalent Network Crystals

• Carbon forms several allotropes (different forms)
  of network solids including the arrangement in
  graphite vs. diamond.
• These arrangements give each type of network
  different chemical and physical properties.

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Practice

• Unknown Solids Worksheet
• Solids Research Worksheet
• P. 273 1-5, 7
• P. 276 1-8