Metals | Metal Ion | Reactivity |
---|---|---|
K | K+ | reacts with water |
Ca | Ca2+ | |
Na | Na+ | |
Mg | Mg2+ | reacts with acids |
Al | Al3+ | |
Zn | Zn2+ | |
Fe | Fe2+ | |
Ni | Ni2+ | |
Sn | Sn2+ | |
Pb | Pb2+ | |
H2 | H+ | |
Cu | Cu2+ | highly unreactive |
Hg | Hg2+ | |
Ag | Ag+ | |
Au | Au3+ |
Metals are listed in decreasing ease of oxidation, or increasing ease of reduction. A metal can replace metals listed below it in the activity series, but not above. For example, sodium is highly active and thus able to replace hydrogen from water:
Metals that can replace hydrogen within acids but not water are listed in the middle of the activity series, for example zinc replaces hydrogen in sulfuric acid: The activity series has applications in electrochemistry, where two dissimilar metals are chosen as electrodes of a battery.