molecular+substances,+network+lattices,+layer+lattices


 * //Molecular substances, network lattices and layer lattices and the limitations of the covalent molecular bonding model// **


 * Videos**

Comparing molecules and ionic compounds || media type="custom" key="23302536" Allotropes of carbon || media type="custom" key="23309168" Covalent network and layer lattices ||
 * media type="custom" key="23302518"


 * Common Misconceptions:**
 * Molecules of solids are 'hard', whereas molecules of gases are 'soft'.
 * Vapour molecules weigh less than solid molecules.
 * Molecules themselves expand when heated.
 * The strengths of covalent bonds and intermolecular forces are similar.
 * Electron pairs are shared equally in all covalent bonds.
 * There are no limitations of these bonding models.


 * Interesting Facts:**
 * Diamond is the hardest naturally occurring substance.
 * When an atom of a non-metal shares electrons to gain a stable outer shell, the atom achieves the same electronic configuration of an atom of its nearest noble gas.
 * Lone electron pairs influence a molecule's shape but are not considered a part of the shape.
 * This bonding model does not explain the elemental forms of some period 3 non-metals (e.g. why sulphur form S8 molecules but oxygen forms O2 molecules and phosphorus forms P4 molecules).


 * Resources:**
 * Molecule shapes, Building a molecule and Molecule polarity, from PhET.
 * Small simple molecules and properties and macromolecules and giant covalent structures from Doc Brown.