How does the reactivity series order metals?

The reactivity series orders metals based on their reactivity towards oxygen, water, and acids.

The reactivity series, also known as the activity series, is a list that ranks different metals based on their reactivity. This reactivity is determined by how readily a metal will form a positive ion. The more readily a metal forms a positive ion, the more reactive it is.

The series is established by observing the reactions of metals with water, oxygen, and acids. Metals at the top of the series, such as potassium and sodium, are highly reactive. They react violently with water and oxygen, and even more so with acids. These metals are so reactive that they must be stored under oil to prevent them from reacting with the moisture in the air.

On the other hand, metals at the bottom of the series, like gold and platinum, are very unreactive. They do not readily react with water or oxygen, and do not react with most acids. These metals are often found in their elemental form in nature because they do not readily combine with other elements.

In the middle of the series, metals like iron and zinc are moderately reactive. They will react with oxygen and acids, but not as violently as the metals at the top of the series. They will not react with cold water, but will react with steam.

The reactivity series is a useful tool in predicting the outcomes of metal displacement reactions. In a displacement reaction, a more reactive metal will displace a less reactive metal from a compound. For example, if you put a piece of zinc (a moderately reactive metal) into a solution of copper sulphate (a compound containing the less reactive copper), the zinc will displace the copper from the compound, forming zinc sulphate and leaving behind elemental copper.

Understanding the reactivity series is fundamental in the study of chemistry, particularly when predicting the products of reactions and understanding why certain reactions occur while others do not.