Uploaded by Divine Grace Cagbabanua

Properties and Types of Solids Presentation

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Properties of Solids
• Mechanical Properties
– Rigidity: Solids retain their shape and resist
deformation.
– Hardness: The resistance to scratching or
indentation.
– Brittleness vs. Malleability: Brittle solids break
easily, while malleable solids can be shaped.
• Thermal Properties
–Melting Point: The temperature at
which a solid becomes a liquid.
–Thermal Expansion: Solids expand on
heating due to increased vibration of
particles.
• Electrical Properties
–Conductivity: Depends on the type of
bonding (e.g., metallic solids are good
conductors; covalent network solids
are insulators).
• Optical Properties
– Transparency vs. Opacity: Some solids allow light
to pass through, while others block it.
– Refractive Index: The measure of how much light
bends when passing through the solid.
• Density
– Solids are generally denser than liquids and gases
due to closely packed particles.
Types of Solids
Crystalline Solids
• Definition: Solids in which particles (atoms, ions,
or molecules) are arranged in a regular, repeating
pattern.Examples: Salt (NaCl), Diamond,
Quartz.Properties:Have a definite geometric
shape.
• Sharp melting points (melt at a specific
temperature).
• Exhibit anisotropy (properties vary with
direction).
• High stability due to strong intermolecular forces.
Amorphous Solids
• Definition: Solids in which particles are not arranged in
a regular pattern; they lack a long-range order.
• Examples: Glass, Rubber, Plastic.
• Properties:No definite geometric shape.
• Gradual softening over a range of temperatures (no
sharp melting point).
• Isotropic (properties are the same in all directions).
• Less stable and can flow over time (pseudo-solid
behavior).
TYPES OF CRYSTALS
Ionic Crystals
• Constituent Particles: Positive and negative ions held
together by strong electrostatic forces (ionic bonds).
Examples: Sodium chloride (NaCl), Potassium bromide
(KBr), Magnesium oxide (MgO).
• Properties:
• Hard and Brittle: Strong ionic bonds make ionic crystals
hard but also prone to shattering under force.
• High Melting and Boiling Points: The strong electrostatic
forces require a lot of energy to overcome.
• Poor Electrical Conductivity in Solid State: Ions are fixed in
place and cannot move.
• Good Electrical Conductivity in Molten or Dissolved State:
Ions become free to move and conduct electricity.
• Solubility: Many ionic crystals dissolve in polar solvents like
water.
Covalent (Network) Crystals
• Constituent Particles: Atoms connected by covalent bonds
in a continuous network throughout the crystal.
Examples: Diamond, Graphite, Silicon dioxide (Quartz),
Silicon carbide (SiC).
• Properties:
• Extremely Hard and Strong: The rigid network of covalent
bonds makes these crystals exceptionally hard (e.g.,
diamond is the hardest natural substance).
• Very High Melting Points: Breaking covalent bonds requires
a large amount of energy.
• Non-conductive (Except Graphite): Electrons are localized
in bonds, except in graphite where delocalized electrons
enable conductivity.
• Insoluble: Covalent crystals are generally insoluble in most
solvents due to the strength of the bonds.
Molecular Crystals
• Constituent Particles: Molecules held together by
weak intermolecular forces (e.g., van der Waals forces,
dipole-dipole interactions, or hydrogen bonds).
Examples: Ice (H₂O), Carbon dioxide (dry ice), Iodine
(I₂), Sugar (C₆H₁₂O₆).
• Properties:
• Soft and Low Melting Points: Weak intermolecular
forces are easy to overcome.
• Non-conductive: Molecules do not have free electrons
or ions to conduct electricity.
• Volatility: Some molecular crystals (e.g., dry ice) easily
sublime due to weak forces.
• Solubility: Depends on the polarity of the molecules;
polar molecular crystals dissolve in polar solvents, and
nonpolar crystals dissolve in nonpolar solvents.
Metallic Crystals
• Constituent Particles: Positive metal ions surrounded by a
"sea of delocalized electrons."
Examples: Iron (Fe), Copper (Cu), Aluminum (Al), Gold (Au).
• Properties:
• Good Electrical and Thermal Conductivity: Delocalized
electrons allow free flow of electric current and heat.
• Malleable and Ductile: The metallic bonds are flexible,
allowing the metal to be shaped without breaking.
• Shiny and Lustrous: Free electrons reflect light, giving metallic
crystals their shiny appearance.
• Variable Melting Points: Melting points depend on the
strength of the metallic bonds (e.g., tungsten has a high
melting point, while mercury is liquid at room temperature).
• High Density: Close packing of metal ions contributes to their
high density.
Gain or Loss
SOLID to LIQUID
LIQUID to VAPOR
VAPOR to SOLID
VAPOR to LIQUID
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