Understanding Metals: Reactivity, Displacement, and Extraction

Reactivity Series of Metals The reactivity series arranges metals based on their tendency to form positive ions. The more reactive a metal, the more easily it l...

Reactivity Series of Metals

The reactivity series arranges metals based on their tendency to form positive ions. The more reactive a metal, the more easily it loses electrons and forms cations.

The reactivity series is as follows (from most to least reactive):

Potassium (K)
Sodium (Na)
Calcium (Ca)
Magnesium (Mg)
Aluminum (Al)
Carbon (C)
Zinc (Zn)
Iron (Fe)
Tin (Sn)
Lead (Pb)
Copper (Cu)
Silver (Ag)
Gold (Au)
Platinum (Pt)

Displacement Reactions

A displacement reaction occurs when a more reactive metal displaces (or replaces) a less reactive metal from its compound. The general equation:

Metal A + Salt of Metal B → Salt of Metal A + Metal B

Worked Example

Problem: Write a balanced equation for the reaction between magnesium and copper sulfate solution.

Solution:

Magnesium is more reactive than copper in the reactivity series.
Magnesium will displace copper from copper sulfate: Mg(s) + CuSO4(aq) → MgSO4(aq) + Cu(s)

Metal Extraction

Most metals are extracted from their ores via reduction processes like smelting or electrolysis. The choice depends on the metal's reactivity.

Extraction of Reactive Metals

Reactive metals like sodium and aluminum are extracted by electrolysis of their molten compounds.

Aluminum Extraction via Electrolysis

Aluminum oxide is dissolved in molten cryolite to lower the melting point.
Passing an electric current causes Al3+ ions to gain electrons at the cathode, forming aluminum metal.
At the anode, oxygen gas is formed from the oxide ions, O2-.

Extraction of Less Reactive Metals

Less reactive metals like iron are extracted by reduction with carbon (coke) in a blast furnace.

Iron Extraction from Hematite (Fe2O3)

Hematite ore is heated with carbon (coke) and hot air in a blast furnace.
Carbon monoxide reduces the iron(III) oxide to iron metal: Fe2O3 + 3CO → 2Fe + 3CO2

Through displacement reactions and extraction processes, metals can be effectively obtained and used for various applications.