Reactivity Series of Metals
The reactivity of metals demonstrate their tendency to undergo chemical reactions, typically by losing electrons to form positively charged ions. The reactivity of metals generally increases when we move top to bottom in a group of the periodic table and decreases as you move across a period.
Chart of the reactivity series of common metals
This series indicates that metals on the top of the list(e.g., potassium) are more reactive, meaning they are more likely to lose electrons and form positive ions in any chemical reactions. Same ways, metals at bottom of the list(e.g., gold) are less reactive and are less likely to undergo any chemical reactions.
General trend in reactivity
1. Alkali metals: Group 1 metals(e.g., lithium, sodium, potassium) are highly reactive, instantaneously reacting with water to form hydroxides and release hydrogen gas.
In alKlai metals reactivity decreasesas we move upwards in group 1 metal period.
Reaction with water:
Na + H₂O→ NaOH + H₂
K + H₂O→ KOH + H₂
Na + HCl→ NaCl + H₂
K + HCl→ KCl + H₂
3. Transition metals: These metals have varying reactivity, with some being quite reactive(e.g., zinc, iron) and others are less reactive(e.g., copper, silver).
4. Halogens: These non-metals are highly reactive, especially towards metals. Ex, fluorine is the most reactive halogen and can even react with noble gases.
5. Noble gases: These gases are generally unreactive under normal conditions due to their complete shells.
The Reactivity Series: Applications
The reactivity of metals is important in various industrial processes,like metal extraction and corrosion resistance, also in the understanding of chemical reactions in biological systems.
The reactivity series is essential in helping us to understand the outcomes of displacement reactions and to predict the behavior of metals in various chemical processes, including metal extraction and corrosion.
More applications of Reactivity Series in chemical reaction:
1. Predicting displacement reactions: The reactivity series helps us to tell whether a metal will displace another metal from its compound in a single displacement reaction. A more reactive metal can displace a less reactive metal from its compound. Ex: according to the reactivity series, zinc can displace copper from copper sulfate solution:
2. Selecting suitable metals for specific applications: Knowledge of the reactivity series helps us to selectappropriate metals for various purposes. For instance, metals higher in the reactivity series are suitable for sacrificial anodes in cathodic protection systems to prevent corrosion of less reactive metals.
3. Understanding redox reactions: The reactivity series is essential in understanding redox reactions. In redox reactions, more reactive metals tend to lose electrons(undergo oxidation) more easily as compared to less reactive metals. This understanding is crucial in balancing redox equations and classifying the direction of electron transfer.
4. Identifying trends in periodicity: The reactivity series provides insights into the periodic trends of metals. Metals higher in the reactivity series tend to be found towards the bottom left of the periodic table, whereas less reactive metals are often located towards the upper right of periodic table.
The Reactivity Series: MCQ
Question 1: Which of the following metals is the most reactive according to the reactivity series?
a) Zinc
b) Iron
c) Sodium
d) Copper
Explanation:
Sodium is more reative then other metals like zinc, iron and copper as it is on the second position from top, so it is more reactive.
Question 2:Which metal is least reactive according to the reactivity series?
a) Sodium
b) Potassium
c) Lead
d) Platinum
Explanation:
According to the reactivity series of metals Platinum lies on the bottom , so it is the least reactive metal amongst all the options available.
Question 3: A metal X is added to a solution of copper sulfate. Which statement is true if X is below copper in the reactivity series?
a) X displaces copper from the solution.
b) No reaction occurs.
c) Copper displaces X from the solution.
d) A precipitate of copper forms.
Explanation:
As the metal X is added to the copper sulfate solution and also metal X is below copper in reactivity series so the metal can't dicsplce copper from it's sulfate. Therefore, no reaction takes place.
Question 4: Which metal reacts vigorously with both water and dilute hydrochloric acid?
a) Magnesium
b) Aluminum
c) Lead
d) Silver
Explanation:
Since Magnesium is very reactive metal, it reacts with dilute hydrochloric acid vigorously realasing hydrogen gas.
Question 5: Which metal is placed below copper in the reactivity series?
a) Gold
b) Silver
c) Zinc
d) both(a)and(c)
Explanation:
Copper is third last element placed in reactivity series and below it are gold and silver.
Question 6: A metal M is added to a solution of zinc sulfate. Which statement is true if M is above zinc in the reactivity series?
a) M displaces zinc from the solution.
b) No reaction occurs.
c) Zinc displaces M from the solution.
d) A precipitate of zinc forms.
Explanation:
As metal M is more reactive then Zinc so it will diplace zinc from it's solution and make a new solution.
Question 7: Which of the following metals does NOT react with dilute hydrochloric acid?
a) Zinc
b) Iron
c) Aluminum
d) Copper
Explanation:
Copper is below hydrogen in reactivity series. So copper is less reactive then hydrogen so it can't displace hydrogen from it's compound.
Question 8: Which metal is commonly used as a catalyst in the hydrogenation of vegetable oils?
a) Nickel
b) Gold
c) Silver
d) Lead
Explanation:
Nickel is more reactive then hydrogen so it will displace hydrogen from it's compound and increase the rate of reaction.
Question 9:In the reaction between hydrochloric acid and magnesium, what gas is evolved?
a) Oxygen
b) Nitrogen
c) Hydrogen
d) Chlorine
Explanation:
Whenever a metal reacts with an acid then a new compound and hydrogen gas is evolved.
Question 10:A metal Y reacts with dilute hydrochloric acid but not with water. Which metal from the reactivity series could Y be?
a) Sodium
b) Iron
c) Copper
d) Gold
Explanation:
