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Crystals-Crystals are solid materials whose atoms are arranged in an orderly,
repeating pattern extending in all three spatial dimensions

Crystal Structure- The crystal structure refers to the specific way in which atoms,
ions, or molecules are arranged in a crystal. This structure is characterized by a repeating
unit called a “unit cell,” which serves as the building block for the entire crystal lattice.

BCC)body-centered cubic

(FCC)face-centered cubic

Lattice Structure: he arrangement of atoms in a crystal can be visualized as a grid,
or “lattice,” where each point in the lattice represents the position of an atom.

Symmetry: Crystalline structures are highly symmetrical. The symmetry can vary
depending on the material, but all crystals exhibit some form of symmetry, which influences
their physical properties, like strength, electrical conductivity, and optical behavior. Example: The salt crystal (sodium chloride)

Types of Crystal Structures:

1. Body-Centered Cubic (BCC)atoms
are positioned at each of the eight corners of
a cube, BCC structure are generally strong and hard

2. Face-Centered Cubic (FCC)- This arrangement allows for a higher
packing density, meaning the atoms are more
closely packed together.

Examples of FCC metals include aluminum, copper, and
gold.

3. Hexagonal Close-Packed (HCP) different from the cubic structures in that it
has a hexagonal shape.

Properties Influenced by Crystal Structure

  • Strength:
  • Flexibility
  • Density:

Metals

    • a class of elements characterized by their unique physical properties
    • typically
      hard, strong, and capable of withstanding high forces, making them suitable for structural
      and load-bearing applications.
    • They are also highly conductive, both electrically and
      thermally, which is essential in electronic and heat management applications.
    • They are versatile
      materials, capable of being alloyed (combined with other elements) to enhance specific
      properties like strength, durability, or corrosion resistance.
  • Common Properties of Metals
    • High Strength:they can
      withstand stretching forces
    • Conductivity: excellent conductors of electricity and heat due to their
      unique atomic structure.
    • Malleability:they can be hammered or rolled into
      thin sheets without breaking.
    • Luster: have a shiny appearance (metallic luster) because they reflect light
      effectively
  • Types of Metallic Structures
    • Metallic Bonding: where free electrons move throughout a “sea of electrons” around positively charged metal
      ions.
    • each metal atom donates one or more of its outer electrons to
      form a collective pool of electrons.
  • Grain Boundaries: they play a
    significant role in determining a metal’s properties. can influence the strength, hardness,
    and durability of metals.

Iron, in its
pure form, is relatively soft and prone to rusting. most widely
used engineering materials due to its high strength
and relatively low cost.

Aluminum is a
lightweight metal with excellent corrosion resistance.good thermal and electrical conductivity, though not as high
as copper.

Copper is well-known for its
excellent electrical and thermal conductivity, second only to silver. widely used in electrical wiring,
motor windings, and plumbing due to its high conductivity and
corrosion resistance. copper is used in heat exchangers,
radiators, and air conditioning systems because of its ability to
transfer heat efficiently.

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Polymers

    • large molecules made up of long chains of repeating units called monomers.
    • monomers are bonded together in a process called polymerization, forming
      complex structures that can be linear, branched, or cross-linked
    • Polymers are incredibly versatile due to the variety of possible monomers
      and structures.
  • Types of Polymers
    • Thermoplasticspolymers that can be repeatedly melted and reshaped
      upon heating.
    • Thermosets-thermosets have a rigid, cross-linked structure, which
      makes them hard and inflexible once they are set. making it impossible
      to remelt or reshape.
    • Elastomershighly elastic properties, meaning
      they can be stretched and return to their original
      shape.
  • Nanomaterials-about 100,000 times smaller than the width of
    a human hair.

Types of Nanomaterials

    • Nanoparticlesspherical particles with
      diameters in the nanoscale range.
    • Nanotubes- cylindrical structures with
      unique properties, especially when made of
      materials like carbon
  • Applications of Nanomaterials
    • Electronics: Nanomaterials are used in
      the electronics industry to create
      smaller, faster, and more efficient
      devices.
    • Medical Treatments: In medicine,
      nanomaterials are used in drug
      delivery, imaging, and diagnostics.
    • Coatings: Nanomaterials are used in coatings to improve durability, resistance to
      scratches, and even antibacterial properties.
    • Energy Storage: Nanotechnology is revolutionizing energy storage, especially in batteries
      and supercapacitors.
  • NUCLEAR CHEMISTRY

  • TYPES OF NUCLEAR DECAY
    • ALPHA DECAY -HE reaction in which alpha particle is ejected
    • BETHA DECAY-neutron decays into a proton and electron
    • GAMMA DECAY-high energy poton release
    • ELECTRON CAPTURE-the first shell is captured by nucleus
    • POSITRON EMISSION

Post Author: Vin X Ce

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