When a metal is placed into a solution with another metal compound (or hydrogen compound such as HCl), a single displacement reaction may or may not occur. A + BC → ?

If a reaction occurs, the elemental metal has displaced the ions from the solution. This means the element is more reactive than the metal (or hydrogen) in solution. Often, the displaced ions can be seen as solid bits or attached to the original metal (ex: zinc turns black). If the displaced ions are hydrogen, they will form hydrogen gas bubbles. If no reaction occurs, the elemental metal is less reactive than the metal in solution.

From single displacement reactions it is easy to see some metals are more reactive than others. For instance, when iron and copper sulfate are placed together in solution (aq), the iron seems to "steal" the sulfate from the copper. We say the iron has ‘displaced’ the copper. However, when copper is placed in solution with iron sulfate, no reaction occurs! This means if an activity series were created with the more reactive metal on top and the less reactive metal on the bottom, the result would be:

Iron Copper By performing a series of single displacement rxns using metals and solutions containing metal ions, a more complete activity series can be created.

Activity Series Li Ca Mg Al Zn Fe Sn H Cu Ag A metal higher in the chart is more reactive and therefore more stable as a compound/ion than as an element. It will displace any metal below it in the chart. Ca + MgSO 4 → Mg + CaSO 4 Mg + CaSO 4 → No Reaction

Non-metals, specifically halogens, have an activity series also. Fluorine is the most reactive: F>Cl>Br>I So.... F 2 + KI → I 2 + KF will occur I 2 + KF → NR will not! F Cl Br I