Metallic Bonding

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Metallic Bonding

• Intermolecular Forces

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Basic metallic properties
Malleable metals can be shaped into thin sheets
Ionic solids are brittle
Ductile metals can be drawn into wires.
Metals are good conductors of electricity.
Metals are good conductors of heat.
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Properties of metals based on molecular structure
- close-packed in structure.
- each atom surrounded by 8 to 12 adjacent atoms
- e- are mobile
not confined to any particular metal ion (0
electrostatic attraction)
evenly distributed
Electron-Sea Model
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Alloy material that contains more than 1 element
and has characteristic properties of metals.
Primary method of modifying properties of pure
metals
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Intermolecular Forces
Intermolecular forces are forces that exist
between molecules.
contribute to properties of solids, liquids,
gases
Ex. melting boiling point
weaker than ionic or covalent bonds
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Types of intermolecular forces
- Ion-dipole attractions
- Dipole-dipole attractions
- Hydrogen bonding
- London dispersion forces
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Ion-dipole attractions
They occur between an ion and the partial charge
on the end of a polar molecule.
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Dipole-dipole attractions
These forces occur when neutral polar molecule
attract each others.
- ends are in close proximity to each other
Weaker than ion-dipole attractions
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London dispersion forces
Occur when a temporary dipole is induced on a
nonpolar molecule/atom by e- from another
nonpolar molecule/atom.
Ex. He(g)
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Hydrogen Bonding
H-bonding is a special type of intermolecular
attraction between the H atom in a polar bond and
a nonbinding e- pair on a small electronegative
ion or atom
Typical H-bonding pairs include
H-O H-F H-N
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H-bonding in H2O causes hexagonal cavities to
form in its solid state.
Due to increased distance between molecules.
H2O is less dense when frozen
H2O expands when frozen