<P> In chemistry, a reactivity series (or activity series) is an empirical, calculated, and structurally analytical progression of a series of metals, arranged by their "reactivity" from highest to lowest . It is used to summarize information about the reactions of metals with acids and water, double displacement reactions and the extraction of metals from their ores . </P> <Table> <Tr> <Th> Metal </Th> <Th> Ion </Th> <Th> Reactivity </Th> <Th> Extraction </Th> </Tr> <Tr> <Td> Caesium Cs </Td> <Td> Cs </Td> <Td> react with cold water </Td> <Td> electrolysis </Td> </Tr> <Tr> <Td> Francium Fr </Td> <Td> Fr </Td> </Tr> <Tr> <Td> Rubidium Rb </Td> <Td> Rb </Td> </Tr> <Tr> <Td> Potassium K </Td> <Td> </Td> </Tr> <Tr> <Td> Sodium Na </Td> <Td> Na </Td> </Tr> <Tr> <Td> Lithium Li </Td> <Td> Li </Td> </Tr> <Tr> <Td> Barium Ba </Td> <Td> Ba </Td> </Tr> <Tr> <Td> Radium Ra </Td> <Td> Ra </Td> </Tr> <Tr> <Td> Strontium Sr </Td> <Td> Sr </Td> </Tr> <Tr> <Td> Calcium Ca </Td> <Td> Ca </Td> </Tr> <Tr> <Td> Magnesium Mg </Td> <Td> Mg </Td> <Td> reacts very slowly with cold water, but rapidly in boiling water, and very vigorously with acids </Td> </Tr> <Tr> <Td> Beryllium Be </Td> <Td> Be </Td> <Td> react with acids and steam </Td> </Tr> <Tr> <Td> Aluminium Al </Td> <Td> Al </Td> </Tr> <Tr> <Td> Titanium Ti </Td> <Td> Ti </Td> <Td> reacts with concentrated mineral acids </Td> <Td> pyrometallurgical extraction using magnesium, or less commonly other alkali metals, hydrogen or calcium in the Kroll process </Td> </Tr> <Tr> <Td> Manganese Mn </Td> <Td> Mn </Td> <Td> react with acids; very poor reaction with steam . </Td> <Td> smelting with coke </Td> </Tr> <Tr> <Td> Zinc Zn </Td> <Td> Zn </Td> </Tr> <Tr> <Td> Chromium Cr </Td> <Td> Cr </Td> <Td> aluminothermic reaction </Td> </Tr> <Tr> <Td> Iron Fe </Td> <Td> Fe </Td> <Td> smelting with coke </Td> </Tr> <Tr> <Td> Cadmium Cd </Td> <Td> Cd </Td> </Tr> <Tr> <Td> Cobalt Co </Td> <Td> Co </Td> </Tr> <Tr> <Td> Nickel Ni </Td> <Td> Ni </Td> </Tr> <Tr> <Td> Tin Sn </Td> <Td> Sn </Td> </Tr> <Tr> <Td> Lead Pb </Td> <Td> Pb </Td> </Tr> <Tr> <Td> Antimony Sb </Td> <Td> Sb </Td> <Td> may react with some strong oxidizing acids </Td> <Td> heat or physical extraction </Td> </Tr> <Tr> <Td> Bismuth Bi </Td> <Td> Bi </Td> </Tr> <Tr> <Td> Copper Cu </Td> <Td> Cu </Td> </Tr> <Tr> <Td> Tungsten W </Td> <Td> </Td> </Tr> <Tr> <Td> Mercury Hg </Td> <Td> Hg </Td> </Tr> <Tr> <Td> Silver Ag </Td> <Td> Ag </Td> </Tr> <Tr> <Td> Gold Au </Td> <Td> Au </Td> </Tr> <Tr> <Td> Platinum Pt </Td> <Td> Pt </Td> </Tr> </Table>

What do you mean by reactive series of metal