The reaction chemistry of aqueous copper(II) ions with ammonia is commonly used in both general chemistry and inorganic chemistry texts to illustrate the equilibria of complex ions in solution.  Although the system initially seems simple, further analysis of the chemical species involved shows that it is in fact quite complicated.  First of all, ammonia is a weak base and its basic equilibrium reaction must be taken into account.  Second, although the aquated copper(II) ion is the most prevalent ion in solution before ammonia is added, this species is itself a weak acid.  Third, a series of

Students assigned a portion of the periodic table.  Generally, a student is given a column of the main group, but this can easily be varied, depending on the size of the class.

I have students construct Lewis structures on the board starting at the noble gases and working backwards to the group 14 elements.  We talk about both second period then heavier elements.  As we move across the period we transition from molecular solids to extended solids.  

This is a nice transition from molecular chemistry to extended compounds.  I use this as a bridge into the solid state portion of the course because it allows me to review Lewis structures, trends in bond energies, and provide some descriptive chemistry information.