bonding

• what are intermolecular forces?


  forces between molecules
• what are 3 types of intermolecular forces?


  induced dipole-dipole(Van Der Waals), permanent dipole-dipole and hydrogen bonds
• what is an induced dipole-dipole?


  electrons move in the orbitals, this might create an 'instantaneous dipole', creates a polar bond
• what is a permanent dipole-dipole?


  occurs between polar molecules, increases energy needed to separate molecules
• what is hydrogen bonding?


  occurs with molecules where H is covalently bonded to an F, O or N, strongest intermolecular force
• what are the characteristics of diamond?

  pure carbon structure with covalent bonds, tetrahedron structure, very high MP, very hard, 3 dimensional lattice, does not conduct electricity, no free particles
• what are the physical properties of graphite?

  giant carbon structure, consists of covalent bonds and van der waals forces, trigonal planar structure, sea of delcolised electrons, can conduct electricity, soft material, high MP, conducts electricity along planes
• what is electronegativity?


  the power of an atom to attract electron density in a covalent bond towards itself
• what is an example of a non-polar bond?

  Cl------Cl
• what is an example of a polar bond?

  Cl------H
• what is the scale that measures electronegativity?

  pauling scale
• what is the electron pair repulsion theory?

  pairs of electrons are going to repel each other making them move to position around the central atoms so they are as far away as possible (VSEPR)
• what is metallic bonding?

  between metals, sea of delocalised electrons, strong bonds, high MP and BP, good conductors of electricity
• what effects the strength of metallic bonds?

  size of charge, size of ion
• what is covalent bonding?

  when 2 or more atoms share 1 or more pairs of electrons
• what is an example of a covalent bond?

  H2O
• what is ionic bonding?

  metal and non-metal, metals lose outer electrons, non-metals have spaces in outer shell that want to get filled
• what are the physical properties of iodine?

  molcular crystal, strong covalent bonds, lots of electrons so VDW forces, easily broken, low melting point and sublimes to form gaseous iodine molecules, does not conduct electricity