Question

What is meant by the reactivity series of metals?

Answer 1

Hint: Electrodes undergo oxidation and reduction. Reduction potential value determines the reactivity of the elements. More negative the reduction potential, more active the element.

Complete step by step solution:
Electrochemistry is the study of inter-conversion of electrical energy and chemical energy. Electrochemical cells convert chemical energy to electric energy. Electrochemical cells are made up of electrodes. Conductors which pass electricity through them are termed as electrodes. There will be two electrodes in an electrochemical cell. One electrode undergoes oxidation and another undergoes reduction. Potential at which the electrodes are prone to gain electrons are called reduction potential. Standard Hydrogen Electrode abbreviated as SHE is the basis for these potentials.
Electrodes are arranged in the order of their reduction or oxidation potentials. This series of arrangements is called electrochemical series or reactivity series or activity series. This is done with reference to the standard hydrogen electrode. The electrodes include both metals and nonmetals. Some of them have positive potential values. They act as cathodes. They get reduced easily. Some others have negative potential values. They act as anodes and help others to get reduced.
Major properties of electrochemical series are:
SHE is kept in the middle of the series. Other elements are kept with respect to SHE.
Elements having negative reduction potentials are kept above the hydrogen. It indicates that they are stronger reducing agents than hydrogen.
Elements having positive reduction potentials are kept below hydrogen. They are weaker reducing agents than hydrogen. They are stronger oxidizing agents than hydrogen.

Additional information:
Activity of metal depends on the ability to form cation or ability to lose electrons. A metal is said to be active if its reduction potential is a smaller positive value. Then it converts to a cation.

Note: Reactivity is highest at the top. It decreases top to bottom. Elements having higher negative potential value have the ability to displace those with lower negative value or higher positive value.