Metals and Non-metals
Elements are broadly divided into metals and non-metals, each with characteristic properties. This chapter compares their physical and chemical behaviour, introduces the reactivity series, explains how metals form ionic compounds, outlines how metals are extracted from their ores, and discusses corrosion and how to prevent it. It is a core, well-rewarded chapter in Class 10 Chemistry.
Learning objectives
- Compare the physical properties of metals and non-metals.
- Arrange metals using the reactivity series.
- Explain the formation of ionic compounds.
- Describe the basic steps of extracting metals from ores.
- Explain corrosion and methods to prevent it.
Key concepts
Physical properties
Metals are usually lustrous, malleable, ductile, sonorous and good conductors of heat and electricity; most are solids with high melting points. Non-metals are generally dull, brittle, poor conductors (except graphite) and may be solids, liquids or gases.
Chemical properties and the reactivity series
Metals react with oxygen to form basic oxides, with water and acids to release hydrogen, and can displace less reactive metals from their salts. The reactivity series (K, Na, Ca, Mg, Al, Zn, Fe, Pb, H, Cu, Ag, Au) ranks metals from most to least reactive.
Ionic compounds
When a metal loses electrons and a non-metal gains them, oppositely charged ions form and are held by strong electrostatic forces — an ionic bond. Ionic compounds have high melting points and conduct electricity when molten or dissolved.
Extraction and corrosion
Metals are extracted from ores by methods that depend on reactivity: highly reactive metals by electrolysis, moderately reactive by reduction of their oxides, and unreactive metals found free. Corrosion (e.g. rusting) is prevented by painting, oiling, galvanising, or alloying.
Important formulas
Metal + oxygen
metal + O₂ → metal oxide (basic)
Metal + acid
metal + dilute acid → salt + hydrogen gas
Reactivity series
K Na Ca Mg Al Zn Fe Pb (H) Cu Ag Au
Key definitions
- Malleability
- The property of being beaten into thin sheets (a property of metals).
- Ductility
- The property of being drawn into wires (a property of metals).
- Ore
- A mineral from which a metal can be profitably extracted.
- Alloy
- A homogeneous mixture of a metal with one or more metals or non-metals (e.g. steel, brass).
Solved examples
Q1. Why is sodium stored under kerosene?
Solution: Sodium is so reactive that it catches fire when exposed to air and reacts vigorously with moisture. Kerosene keeps air and water away, preventing these reactions.
Q2. What happens when zinc is added to copper sulphate solution?
Solution: Zinc, being more reactive than copper, displaces it: Zn + CuSO₄ → ZnSO₄ + Cu. The blue colour fades and reddish copper is deposited.
Q3. Why does iron rust, and how can rusting be prevented?
Solution: Iron reacts with oxygen and moisture to form hydrated iron oxide (rust). It is prevented by painting, oiling, greasing, galvanising (zinc coating) or making alloys like stainless steel.
Common mistakes to avoid
- Calling all metals solids — mercury is a liquid at room temperature.
- Saying non-metals never conduct electricity — graphite (a non-metal) conducts.
- Reversing the reactivity series order.
- Confusing minerals with ores (all ores are minerals, but not all minerals are ores).
Metals and Non-metals — MCQ Quiz
11 questions with instant feedback. Use number keys 1–4 to answer.
Which property allows metals to be drawn into wires?
Practice questions
Short answer
Why are metals sonorous?
They produce a ringing sound when struck, which is why they are used in bells and wires.
Name two metals that are found in a free state in nature.
Gold and silver (and platinum) — they are unreactive.
What is an amalgam?
An alloy in which one of the metals is mercury.
Long answer
Explain how the reactivity series helps in displacement reactions, with an example.
A metal higher in the reactivity series can displace a metal lower than it from the latter's salt solution. For example, iron (higher) displaces copper (lower): Fe + CuSO₄ → FeSO₄ + Cu. A less reactive metal cannot displace a more reactive one.
Describe how moderately reactive metals are extracted from their oxide ores.
Their ores are first converted to oxides (by roasting sulphide ores or calcining carbonate ores). The oxide is then reduced to the metal using a reducing agent such as carbon (e.g. ZnO + C → Zn + CO). Finally, the metal is refined, often by electrolysis.
HOTS (Higher Order Thinking)
Why does silver jewellery turn black over time?
Silver reacts slowly with sulphur compounds in the air to form a black coating of silver sulphide — a form of corrosion specific to silver.
Aluminium is reactive, yet it resists corrosion. Why?
Aluminium forms a thin, hard, unreactive layer of aluminium oxide on its surface that protects the metal underneath from further reaction.
Quick revision
Revision notes
- Metals: lustrous, malleable, ductile, sonorous, good conductors.
- Non-metals: dull, brittle, poor conductors (graphite is an exception).
- Reactivity series: K Na Ca Mg Al Zn Fe Pb (H) Cu Ag Au.
- Extraction by reactivity; corrosion prevented by coating/alloying.
Key takeaways
- Reactivity decides both displacement reactions and the method of extraction.
- Ionic compounds form between metals and non-metals.
- Know the standard exceptions (mercury, graphite, aluminium oxide layer).
Frequently asked questions
What is the reactivity series used for?
To predict displacement reactions and to choose the right method for extracting a metal from its ore.
Why do ionic compounds conduct electricity only when molten or dissolved?
Their ions are fixed in a solid lattice but become free to move when the compound is melted or dissolved, allowing it to conduct.
What is the difference between a mineral and an ore?
A mineral is any naturally occurring substance containing a metal; an ore is a mineral from which the metal can be extracted profitably.