Ch. 6 Bonding

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Ch. 6 Bonding

• 6.3 Ionic Bonding
• McFall

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Ionic Compounds

• ionic bonds do NOT form molecules
• chemical formulas for ionic compounds represent
  the simplest ratio of ion types
• made of anions and cations

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Ionic Compounds

• combined so that amount of positive and negative
  charge is equal
• usually crystalline solid
• formula of ionic compound depends of the charges
  of the ions combined

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Formation

• attractive forces
• oppositely charged ions
• nuclei and electron clouds of adjacent ions
• repulsive forces
• like-charged ions
• electrons of adjacent ions

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Formation

• distance between the ions creates a balance
  between those forces
• ions minimize their PE by combining in an orderly
  arrangement called a crystal lattice

6
Formation

• specific lattice pattern created depends on
• charges of ions
• size of ions

Calcium Bromide each Ca2 is surrounded by 8
F- each F- is surrounded by 4 Ca2
Sodium Chloride each Na is surrounded by 6
Cl- each Cl- is surrounded by 6 Na
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Lattice Energy

• energy released when separate gaseous ion bond to
  form ionic solid
• the larger the amount of energy released, the
  stronger the bond
• since it is released, the value is negative

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Ionic vs. Molecular

• ionic bonds and molecular bonds are both strong
• ionic bonds connect all ions together
• molecules are more easily pulled apart because
  intermolecular forces are weak

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Ionic vs. Molecular

• Molecular Compounds
• low melting and boiling points
• many are gases at room temperature
• Because the intermolecular forces of the
  molecules are weak so they are easily separated

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Ionic vs. Molecular

• Ionic Compounds
• higher melting and boiling points
• all are solid at room temperature
• hard Because of the strong forces, it is
  difficult for one layer of ions to move past
  another
• brittle if one layer is moved, the layers come
  apart completely

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Ionic vs. Molecular

• Ionic Compounds
• good conductors in liquid state
• Because ions are free to move and carry charge
• poor conductor in solid state
• Because ions are fixed in place

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Ch. 6 Bonding

• Metallic Bonding

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Bonding of Metals

• the highest energy level for most metal atoms
  does not contain many electrons
• usually have empty p and d block
• these vacant overlapping orbitals allow outer
  electrons to roam freely around the entire metal
• the electrons are delocalized are not with one
  specific atom

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Bonding of Metals

• these roaming electrons
• form a sea of electrons
• around the metal atoms
• metal atoms are packed in a crystal lattice
• metallic bonding bonding that results from the
  attraction between metals atoms and sea of
  electrons

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Properties of Metals

• conductivity
• from the freedom of electrons to move around the
  atoms
• luster (shininess)
• contain many orbitals with only small differences
  in energy
• many amounts of energy can be absorbed and emitted

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Properties of Metals

• malleability and ductility
• bonding is the same in every direction
• one layer of atoms can slide past another without
  friction

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Bond Strength

• depends on the nuclear charge (Z) or the number
  of protons
• depends on the number of electrons in the sea
• heat of sublimination amount of heat required
  to turn solid, bonded metal atoms into gaseous
  individual atoms

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Metallic vs. Ionic