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Metals and Non-metals – Class 10 Science notes, important questions and MCQs

NCERT Class 10 Science, chapter 3. Notes, key terms, important questions with answers and MCQs.

Chapter overview

Metals are usually shiny, malleable, ductile and good conductors; non-metals are mostly the opposite. Their reactivity decides how they react and how metals are extracted.

Properties

Metals: lustrous, malleable, ductile, sonorous, good conductors (silver and copper best); mercury is liquid.
Non-metals: dull, brittle, poor conductors; graphite conducts electricity; iodine is lustrous.
Metal oxides are basic (some like Al₂O₃, ZnO are amphoteric); non-metal oxides are acidic or neutral.

Reactivity series (high to low)

K > Na > Ca > Mg > Al > Zn > Fe > Pb > H > Cu > Hg > Ag > Au.
Metals above hydrogen displace it from dilute acids.
Sodium and potassium are kept in kerosene because they react violently with air and water.

Ionic compounds and extraction

Metals lose electrons and non-metals gain them to form ionic compounds (e.g. NaCl); these have high melting points and conduct when molten or dissolved.
Low-reactivity metals: heat the ore. Middle: roast/calcine, then reduce with carbon. High: electrolysis of molten ore.
Corrosion is prevented by painting, oiling, galvanising (zinc coat) and alloying.

Key terms

Malleable: can be beaten into thin sheets
Ductile: can be drawn into wires
Amphoteric oxide: oxide reacting with both acids and bases
Alloy: a homogeneous mixture of a metal with other elements (e.g. brass, bronze, steel)

Formulas

2Na + 2H₂O → 2NaOH + H₂
Fe₂O₃ + 2Al → 2Fe + Al₂O₃ (thermit reaction)
Brass = Cu + Zn; bronze = Cu + Sn; solder = Pb + Sn

Important questions with answers

Why is sodium kept immersed in kerosene?2 marks

Sodium reacts vigorously with oxygen and moisture in air and can catch fire. Kerosene keeps air and water away from it.

Show the formation of NaCl by the transfer of electrons and give two properties of ionic compounds.3 marks

Na (2, 8, 1) loses one electron to become Na⁺; Cl (2, 8, 7) gains it to become Cl⁻; the oppositely charged ions attract to form Na⁺Cl⁻. Ionic compounds have high melting and boiling points and conduct electricity in molten state or in water solution.

Explain the extraction of a moderately reactive metal such as zinc from its sulphide ore. Write the equations.5 marks

The ore is first concentrated. Zinc sulphide is roasted (heated strongly in excess air): 2ZnS + 3O₂ → 2ZnO + 2SO₂. The oxide is then reduced with carbon: ZnO + C → Zn + CO. The impure zinc is refined, for example by electrolytic refining. Sulphide and carbonate ores are converted to oxides because metals are easier to obtain from oxides.

Quick revision

Most reactive common metal: potassium; least: gold.
Galvanising = zinc coating on iron.
Ionic compounds conduct electricity in molten or solution form.

Exam tips

Roasting is heating a sulphide ore in air; calcination is heating a carbonate ore in limited air.
Aqua regia (3 HCl : 1 HNO₃) dissolves gold and platinum.

Practice MCQs

Which metal is liquid at room temperature?
1. mercury
2. sodium
3. iron
4. aluminium
Show answer
Answer: (a) mercury. Mercury is liquid.
The property of being drawn into wires is
1. malleability
2. sonority
3. ductility
4. lustre
Show answer
Answer: (c) ductility. Ductility.
Which non-metal conducts electricity?
1. sulphur
2. iodine
3. phosphorus
4. graphite
Show answer
Answer: (d) graphite. Graphite has free electrons.
Sodium is stored in kerosene because it
1. is very soft
2. reacts vigorously with air and water
3. is costly
4. is heavy
Show answer
Answer: (b) reacts vigorously with air and water. It catches fire in air.
Which metal will NOT displace hydrogen from dilute HCl?
1. zinc
2. copper
3. magnesium
4. iron
Show answer
Answer: (b) copper. Copper is below hydrogen in the series.
Al₂O₃ reacts with both acids and bases, so it is
1. amphoteric
2. acidic
3. basic
4. neutral
Show answer
Answer: (a) amphoteric. Amphoteric oxide.
Galvanisation of iron means coating it with
1. tin
2. zinc
3. copper
4. chromium
Show answer
Answer: (b) zinc. Zinc protects iron from rusting.
The thermit reaction is used for
1. welding railway tracks
2. extracting sodium
3. making steel sheets
4. purifying copper
Show answer
Answer: (a) welding railway tracks. Molten iron from Fe₂O₃ + Al joins rails.

All chapters of Class 10 Science

Written by Kundali IQ from standard, well-established facts to help with revision. This is not an official NCERT publication; always read your textbook too.