Bonding

• Orbital - volume of space which can hold up to 2 electrons of opposite spin
• metallic bonding - sea of delocalised electrons in a giant lattice of cations
• ionic bonding - electrostatic force of attraction between oppositely charged ions
• Covalent bonding - electrostatic force of attraction between the nuclei and shared pair of electrons
• Dative covalent bonding - one atom provides both of the shared electron
• Non polar - even distribution of charge
• polar - uneven distribution of charge
• Intermolecular forces - attractive forces between neighbouring molecules
• properties of metals:

  • conducts electricity and heat in solid and liquid state
  • malleable (bend)
  • high density
  • high boiling and melting point
  • Poor solubility
  • Ductile (layered)
• Compare the strength of metallic bonding in Mg and Na

  • Mg forms 2+ ions and Na forms 1+ ions.
  • Each Mg atom releases 2 electrons and each Na atom releases 1 electron.
  • One more proton in Mg nucleus than Na nucleus.
  • Therefore there is a stronger electrostatic force of attraction between the Mg nucleus and delocalised electron
• Which has a higher melting point, NaCl or MgO?

  MgO due to the ions in MgO attracting more strongly due to a higher ionic charge.

  Therefore more energy is needed to break the ionic lattice.