IRON (Fe) – At a glance

1. Basic Information 

Property	Information
Element	Iron
Symbol	Fe
Atomic number	26
Relative atomic mass	55.85
Group
Period	4
Block	d-block
Nature	Transition metal
Melting point	1538°C
Density	7.87 g/cm³

2. Occurrence of Iron

Iron occurs mainly in the Earth's crust as compounds called ores.

Iron ore	Chemical formula
Haematite	Fe₂O₃
Magnetite	Fe₃O₄
Siderite	FeCO₃
Limonite	Fe₂O₃·xH₂O
Iron pyrites	FeS₂

Most important ore: Haematite (Fe₂O₃).

Note: Iron pyrites is not an important commercial ore for iron extraction because of its high sulphur content.

3. Types of Iron

S/N	Type	Main characteristics
1.	Pig iron	Crude iron from the blast furnace; high carbon content
2.	Cast iron	Hard, brittle and easily cast
3.	Wrought iron	Very low carbon; tough and malleable
4.	Steel	Alloy of iron and carbon; strong and versatile

4. Physical Properties of Iron

1. Silvery-grey in colour.
2. Solid at room temperature.
3. Hard and strong.
4. Malleable – can be hammered into sheets.
5. Ductile – can be drawn into wires.
6. Magnetic – attracted by magnets.
7. Good conductor of heat and electricity.
8. High melting point (1538°C).
9. High density (7.87 g/cm³).
10. Sonorous.

5. Chemical Properties of Iron

Iron reacts with oxygen, water, acids and non-metals.

Reaction	Balanced chemical equation
With oxygen	3Fe + 2O₂ → Fe₃O₄
Rusting	4Fe + 3O₂ + 2xH₂O → 2Fe₂O₃·xH₂O
With steam	3Fe + 4H₂O → Fe₃O₄ + 4H₂
With hydrochloric acid	Fe + 2HCl → FeCl₂ + H₂
With sulphuric acid	Fe + H₂SO₄ → FeSO₄ + H₂
With sulphur	Fe + S → FeS
With chlorine	2Fe + 3Cl₂ → 2FeCl₃
With copper(II) sulphate	Fe + CuSO₄ → FeSO₄ + Cu

6. Rusting of Iron

Rusting is the slow reaction of iron with oxygen and moisture to form hydrated iron(III) oxide.

i. Colour of rust: Reddish-brown.

ii. Conditions required: Oxygen and water.

iii. Rust weakens iron objects.

Prevention of Rusting

1. Painting
2. Oiling and greasing
3. Galvanisation
4. Electroplating
5. Alloying to produce stainless steel
6. Plastic coating

7. Uses of Iron

Application	Use
1. Construction	Buildings, bridges and reinforcement bars
2.Transportation	Cars, ships and railway tracks
3. Agriculture	Hoes, cutlasses and ploughs
4. Manufacturing	Machines and industrial equipment
5. Household	Pots, pans, gates and doors
6. Electrical industry	Transformer cores and electromagnets
7. Plumbing	Pipes and drainage systems

8. Important Examination Facts

1. Symbol of iron: Fe.
2. Atomic number: 26.
3. Most important iron ore: Haematite.
4. Formula of haematite: Fe₂O₃.
5. Formula of magnetite: Fe₃O₄.
6. Formula of siderite: FeCO₃.
7. Formula of iron pyrites: FeS₂.
8. Main raw materials for blast furnace extraction: Iron ore, coke and limestone.
9. Reducing agent in the blast furnace: Carbon monoxide.
10. Flux used in iron extraction: Limestone.
11. Main slag formed: Calcium silicate (CaSiO₃).
12. Main product: Molten pig iron.
13. Common corrosion product: Hydrated iron(III) oxide.

9. Essential Chemical Equations

Reduction of iron ore:

Fe₂O₃ + 3CO → 2Fe + 3CO₂

Decomposition of limestone:

CaCO₃ → CaO + CO₂

Formation of slag:

CaO + SiO₂ → CaSiO₃

10. Quick Revision Questions

1. What is the chemical symbol of iron?
2. State the atomic number of iron.
3. Name four important ores of iron.
4. Which iron ore is represented by Fe₃O₄?
5. What is rusting?
6. State four methods of preventing rusting.
7. What is the difference between cast iron and wrought iron?
8. Which gas reduces iron ore in the blast furnace?
9. What is the function of limestone in iron extraction?
10. Write the equation for the reduction of haematite by carbon monoxide.

Remember: Iron is an important transition metal, and its major industrial importance comes from its use in producing steel and other useful alloys.