What is the reactivity series in chemistry?

The reactivity series in chemistry is a list of elements ordered by their ability to displace another element in a chemical reaction.

The reactivity series, also known as the activity series, is a crucial concept in chemistry, particularly for IGCSE students. It is a list of metals (and hydrogen) arranged in order of their reactivity, starting with the most reactive at the top and the least reactive at the bottom. This series helps us predict how different elements will react with each other.

The reactivity of an element is determined by its ability to lose or gain electrons, which in turn is influenced by the structure of its atoms. Elements at the top of the series, such as potassium and sodium, are very reactive. They readily lose electrons to form positive ions, and can displace less reactive metals from their compounds. For example, if you put a piece of potassium in water, it reacts violently, displacing hydrogen from the water to form potassium hydroxide and hydrogen gas.

On the other hand, elements at the bottom of the series, like gold and platinum, are less reactive. They do not readily lose electrons, and cannot be easily displaced from their compounds by more reactive metals. For instance, if you put a piece of gold in a solution of copper sulphate, no reaction occurs because gold is less reactive than copper.

The reactivity series is not just limited to metals. Non-metals, such as halogens, also have their own reactivity series. For example, chlorine is more reactive than iodine, so it can displace iodine from a solution of potassium iodide.

Understanding the reactivity series is essential for predicting the outcomes of chemical reactions, and for making sense of the chemical behaviour of different elements. It's a fundamental part of your IGCSE Chemistry studies.