2.  Ranking elements in relative order of their
chemical reactivity.

5.  Used to predict whether certain chemical
reactions can be expected.
 A more reactive metal (higher in activity
series) will react with a solution of a less
reactive metal (lower in activity series).
 Will zinc metal react in a magnesium
solution?
 Will zinc metal react in a gold solution?

6.  Mn2+(aq)+ Pb(s) -- Mn(s) + Pb2+
 Mn(s) +Pb2+ -- Mn2+ + Pb(s)