Activity Series

ACTIVITY SERIES
The activity series of metals is an list of metals ranked in order of decreasing reactivity to displace hydrogen gas from water and acid solutions. It can also be used to predict which metals will displace other metals in aqueous solutions.
In introductory chemistry, the reactivity series or activity series is an empirical series of metals, in order of "reactivity" from highest to lowest. It is used to summarize information about the reactions of metals with acids and water, single displacement reactions and the extraction of metals from their ores.
We arrange metals into an ordered list with the best reducing agent at the top and the worst reducing agent at the bottom. This is an Activity Series for metals. Metals near the top of the list give up electrons most easily. Those metals near the bottom of the list give up electrons with difficulty. Hydrogen, even though it is not a metal, can be placed in the list. Metals above hydrogen in the Activity Series will react with 1.0 Molar hydrochloric acid at room temperature. The Activity Series for metals is developed by experiment. * Each element on the list replaces from a compound any of the elements below it. The larger the interval between elements, the more vigorous the reaction. * The first five elements (lithium - sodium) are known as very active metals and they react with cold water to produce the hydroxide and hydrogen gas. * The next four metals (magnesium - chromium) are considered active metals and they will react with very hot water or steam to form the oxide and hydrogen gas. * The oxides of all of these first metals resist reduction by H2. * The next six metals (iron - lead) replace hydrogen from HCl and dil. sulfuric and nitric acids. Their oxides undergo reduction by heating with H2, carbon, and carbon monoxide. * The metals lithium - copper, can combine directly with oxygen to form the oxide. * The last five metals (mercury - gold) are often found free in nature, their oxides decompose with mild heating, and they form oxides only indirectly.