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An activity series is a list of substances listed in order of reactivity.

The metal activity series, from most active to least active:

K (potassium)
Ca (Calcium)
Na (Sodium)
Mg (Magnesium)
Al (Aluminum)
Mn (Manganese)
Zn (Zinc)
Fe (Iron)
Ni (Nickel)
Sn (Tin)
Pb (Lead)

H (Hydrogen)

Cu (Copper)
Ag (Silver)
Pt (Platinum)
Au (Gold)

The activity series is used to predict the products of single-replacement reactions.

Example: Zn + CuSO4 ---> ZnSO4 + Cu

The zinc replaces the copper in copper (II) sulfate because it is more active than copper.

Several things must be noted. First, copper, silver, platinum, and gold are the jewelry metals at the bottom of the activity series. They cannot replace hydrogen in a reaction. Nickel, tin, and lead can only replace hydrogen in acids. Magnesium, aluminum, manganese, zinc, and iron can replace hydrogen from steam or acids, while the remaining elements at the top of the list can displace hydrogen in water, steam or acids.

There is also an activity series for nonmetals. The nonmetal activity series, from most reactive to least reactive, is as follows:

F (Fluorine)
Cl (Chlorine)
O (Oxygen)
Br (Bromine)
I (Iodine)

The most active member of the halogen family (Group VII of the periodic table) is located at the top of the periodic table (Fluorine). Moving down vertically from the top, the elements become less active.

A chemistry teacher of mine thought of it this way: The halogen family consists of four sisters (F, Cl, Br, I). "Fluorine the floozy" (who is a big slut) always steals the "boyfriends" of all her other sisters. Chlorine does not steal "boyfriends" from Fluorine, but Bromine and Iodine. Bromine likewise only steals from Iodine. Poor Iodine always ends up single. Aww.

The activity series works fairly well in normal situations (when the reaction takes place at room temperature in aqueous solution). However, some weird things can happen under other reactions that defy the activity series.

The activity series thus cannot accurately predict products of chemical reactions 100% of the time.


This node was written using personal notes from class. More information can be found at:
http://antoine.frostburg.edu/chem/senese/101/redox/faq/activity-series.shtml

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