Reactivity Series

Reactivity series is an arrangement of metals from highest to lowest reactivity order. Therefore, the term “reactivity series of metal” refers to a series of metals arranged in descending order of reactivity. It is also known by the name “activity series.” The reactivity of metals is due to their electronic structure or to the incomplete outer orbitals. As they tend to lose electrons, metals produce positively charged ions. High atomic number metals are more likely to be reactive since their electrons can be withdrawn with ease because they are separated from the positively charged nucleus.

What is the Reactivity Series?

It has been observed that some metals react quickly and strongly with reactants, while others react slowly, or some do not react at all. This is because of the reactivity of the metal. Here, reactivity means the ability of a chemical substance to give the product on its own. 

The arrangement of metals in a series of decreasing order of their tendencies to react is called the Reactivity Series of metal. Therefore, the least reactive metal (Platinum) is placed at the bottom while, the highly reactive metal (Potassium) is at the top of this series.

To determine if a metal can displace another in a single displacement reaction, the data provided by the reactivity series can be utilized. It can also be used to find out how reactive various metals are to acids and water.

Below is a chart showing the reactivity series of common metals:

Salient Features of Reactivity Series

• The reducing tendency of metals at the top of the table has high, that is why they are easily oxidized. These metals can get tarnished or corrode very easily.
• The electro-positivity (tendency to lose electrons) of the elements gets reduced while moving down the reactivity series of metals.
• The tendency to reduce the metals becomes weaker while traversing down the series.
• On reaction with dilute HCl or dilute H₂SO₄, all metals that are found above hydrogen in the activity series liberate H₂ gas.
• Higher ranking metals require greater amounts of energy for their isolation from ores and other compounds.

Long Tabular Form of the Reactivity Series 

The Reactivity series of some of the most common metals, arranged in descending order of reactivity:

Metal	Ion	Reactivity
Potassium	K+	React with Cold Water
Sodium	Na+
Lithium	Li+
Barium	Ba+
Strontium	Sr+
Calcium	Ca+
Magnesium	Mg+	Reacts very slowly with cold water, whereas quickly in boiling water, and very strongly with acids.
Beryllium	Be2+	Reacts with steam and acids
Aluminium	Al3+
Titanium	Ti4+	Reacts with concentrated mineral acids
Manganese	Mn2+	Reacts with acids
Zinc	Zn2+
Chromium	Cr3+
Iron	Fe2+
Cadmium	Cd2+
Cobalt	Co2+
Nickel	Ni2+
Tin	Sn2+
Lead	Pb2+
Antimony	Sb3+	May react with some strong oxidizing acids
Bismuth	Bi3+
Copper	Cu2+	React slowly with water
Tungsten	W3+	Highly unreactive May react with some of the strong oxidizing acids
Mercury	Hg2+
Silver	Ag+
Gold	Au3+

Important uses of Reactivity Series

The reactivity series provides the study of properties and reactivities of the metals, Apart from this reactivity series also provides several other important applications. For example, the result we get out of the reactions between metals and acids, metals and water, and single displacement reactions between metals can be predicted.

• Reaction Between Metals and Water: Calcium and the metals that are more reactive than calcium in the reactivity series can react with cold water to form the corresponding hydroxide while liberating hydrogen gas. For example, the reaction between potassium and water yields potassium hydroxide and H₂ gas, as described by the chemical equation provided below.

2K + 2H₂O → 2KOH + H₂

• Reaction with Acid and bases: Metals, displace hydrogen from its dilute acids which are more reactive than hydrogen, and form respective metal salts and hydrogen gas.

Metal + dilute acid → Salt + Hydrogen gas

• Sodium metal has a tendency to displace hydrogen from hydrogen chloride (HCl) to form sodium chloride and liberate hydrogen gas. the reaction is given below:

2Na(s) + 2HCl (dilute)  →  2NaCl (aq)  +  H₂(g)

Tricks to Remember Reactivity Series of Metals

The basic strategy for learning the reactivity series is to group these elements into meaningful groups and then use a mnemonic for each group.

Here we have uses the sentence “Please send charlie’s monkeys and zebras in lead & hydrogen cages in mountains securely guarded by Plato.” The first letter of each word represents a metal of the reactivity in the order from highest to lowest as:

Symbol	Metal of the Reactivity Series	Words/Mnemonic used to Remember the Series
K	Potassium	Please
Na	Sodium	Send
Ca	Calcium	Charlie’s
Mg	Magnesium	Monkey
Al	Aluminium	And
Zn	Zinc	Zebra
Fe	Iron	In
Pb	Lead	Lead &
H	Hydrogen	Hydrogen
Cu	Copper	Cages in
Hg	Mercury	Mountains
Ag	Silver	Securely
Au	Gold	Guarded by
Pt	Platinum	Plato

FAQs based on the Reactivity Series of Metals

Question 1: What is the reactivity series of metals?

Answer:

The arrangement of metals in a series of decreasing order of their tendencies to react is called the Reactivity Series of metal. 

Question 2: What does a reactivity series show?

Answer:

Reactivity series shows a list of metals arranged based on their tendencies to react from highest to lowest order. This implies that the most reactive metals are at the top while the least reactive metals at the bottom.

Question 3: Which is the most reactive metal?

Answer:

According to the reactivity series of metals, Potassium (K) is the highly reactive metal.

Question 4: Which metal is the least reactive?

Answer:

According to the reactivity series of metals, Platinum (Pt) is the least reactive metal.

Question 5: What does the reactivity series of metals depend on?

Answer:

The reactivity of metals is determined by its reactivity, which is influenced by the atomic radius, nuclear charge, arrangement of the sublevel electrons, and shielding effect.

Related Resources

• CBSE Class 8 Chemistry Notes for Metals and Non-Metals
• CBSE Class 10 Chemistry Notes for Metals and Non-Metals