Activity Series (Reactivity Series) of Metals
- An activity series is a list of substances in order from most reactive to least reactive.
- The relative reactivity of metals can be determined using a number of chemical reactions.
The most commonly used reactions are reactions with:
(a) water (in which hydrogen is displaced from water to produce hydrogen gas)
(b) non-oxidizing acids such as dilute hydrochloric acid or dilute sulfuric acid (in which hydrogen is displaced from acid to produce hydrogen gas).
- A metal activity series places metals in order of relative reactivity, from most reactive to least reactive:
|most reactive||→ → → → → → → → → → → → → → → → → → → → → → → →||least reactive|
- In general:
- Group 1 (alkali) metals and Group 2 (alkaline earth) metals are more active than transition metals.
(Silver, platinum and gold are so unreactive that they are called noble metals (or inactive metals).
- A more active metal loses electrons more easily than a less active metal.
A more active metal is a stronger reductant than a less active metal.
(A substance that loses electrons is called a reductant or reducing agent)
- A more active element displaces a less active element in a chemical reaction.
Enabling us to make predictions on the probable outcome of a chemical reaction!
- The further apart two elements are in the activity series, the more energy the reaction produces.
Enabling us to predict the relative amount of energy released during a chemical reaction!
- If a reaction occurs, a more active metal will react more rapidly than a less active metal.