Chemical Bonding

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Chemical Bonding
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Chemical Bonding

• Electrical attraction between nuclei of one atom
  and valence electrons of a different atom
• Why does bonding occur?

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Ionic Bonds

• Bond most often between a metal and a nonmetal
• Transfer of electrons from the metal to the
  nonmetal
• Electrical attraction between large numbers of
  cations and anions called clusters
• Ion a charged particle

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Ionic Bonds

• Cation charged particle
• Loves to give electrons away
• Low Ionization Energy, Electron Affinity
  Electronegativity
• Typically are metals
• Most metallic element Fr

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Ionic Bonds (cont.)

• Anion - charged particle
• Loves to accept electrons
• High Ionization Energy, Electron Affinity
  Electronegativity
• Typically are nonmetals
• Most nonmetallic element F

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Ionic bonding

• Ionic bonding involves 3 steps (3 energies)
• 1) loss of an electron(s) by one element,
• 2) gain of electron(s) by a second element,
• 3) attraction between positive and negative

3)
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Ionic Bonds (cont.)

• Ionic compounds are solids (salts)
• Ionic bonds dissociate in water
• Fall apart into cations and anions
• Will conduct electricity
• --EN values 1.8 up to 4

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In General. Ionic Bonds are the strongest
bonds there are!
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Covalent Bonds

• Formed when 2 nonmetal atoms share electrons
• Can be liquid, solid or gas

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Polar Covalent Bonds

• Unequal sharing of electrons
• Electrons attracted more to higher E.N. atom so
  density is greater around atom with higher E.N.
  value
• Electronegativity difference range 0.3 1.7
  (for polar covalent bonds)
• Polar Covalent Bonds dissolve in water
• Dont fall apart into ions
• No conductivity

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Non-polar Covalent Bonds

• Equal sharing of electrons
• Electronegativity difference range 0.0 lt0.3
• Usually found between diatomic molecules two of
  the same atoms
• Non-polar covalent bonds dont dissolve in water.
• No conductivity

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Metallic Bonds

• Bond formed between 2 metal atoms.
• Large outer electron shells which overlap
• Excellent electrical conductors in solid state
• Electrons are free to move within electron clouds
  of all metal ions Sea of Electrons

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Metallic Bonds

• In metals, p-orbitals and some d-orbitals are
  completely vacant and overlap each atom.
• Electrons are delocalized they dont belong to
  any one atom anymore.

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Quick Review

• Ionic bonds are between
• A) metals and non-metals
• B) non-metals
• C) metals
• Answer A) metals and non-metals

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Quick Review

• Covalent bonds are between
• A) metals and non-metals
• B) non-metals
• C) metals
• Answer B) non-metals

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Quick Review

• Metallic bonds are between
• A) metals and non-metals
• B) non-metals
• C) metals
• Answer C) metals

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Quick Review

• The strongest bonds are between
• A) metals and non-metals
• B) non-metals
• C) metals
• Answer A) metals and non-metals (ionic)

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Quick Review

• Ionic bonds at room temperature are
• A) solid
• B) liquid
• C) gas
• D) any
• Answer A) solid
• Can you name some?

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Quick Review

• Covalent bonds at room temperature are
• A) solid
• B) liquid
• C) gas
• D) any
• Answer D) any
• Can you name some?
• HCl (aq), Bromine (aq), Fluorine (g), Diamond (s)

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Quick Review

• Metallic bonds at room temperature are
• A) solid
• B) liquid
• C) gas
• D) any
• Answer A) solid and B) liquid
• What metallic bonds can be liquid at room
  temperature?
• Hg Any ideas why?
• Bond strength not enough to make a solid yet
  strong enough to keep it from being a gas.

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Quick Review

• Which bonds are most likely to dissociate in
  water (water is polar)
• A) ionic
• B) polar covalent
• C) nonpolar covalent
• D) Metallic
• Answer A) ionic