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Grade 7/ Science/ Metals & Non-metals
Chapter 4 · NCERT Curiosity

The World of
Metals & Non-metals

Shiny or dull? Bends or shatters? Carries a current or blocks it? A handful of simple tests sorts almost every material into two great families.

🔩 3 topics⏱ ~25 min📝 12-question quiz
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Play with it

Sort the material

Tap a material and run the four classic tests — lustre, malleability, conductivity and sonority. They line up to tell you: metal or non-metal?

Explore · Material testertap a material

Learn

The three big ideas

Metals usually are:

  • Lustrous — shiny when polished.
  • Malleable — can be beaten into sheets (foil); ductile — can be drawn into wires.
  • Good conductors of heat and electricity.
  • Sonorous — ring when struck.

Non-metals are usually the opposite: dull, brittle (break when hit), and poor conductors (insulators).

These are general trends, and nature loves exceptions:

  • Graphite (a form of carbon, a non-metal) conducts electricity.
  • Iodine is a non-metal but is lustrous.
  • Sodium & potassium are metals but so soft you can cut them with a knife.
  • Mercury is a metal that is liquid at room temperature.
Common mistake: treating the properties as unbreakable rules. They're strong patterns — always look for the odd one out (like conducting graphite).
  • With oxygen: metals form basic oxides; non-metals form acidic oxides.
  • Rusting: iron + oxygen + moisture → reddish-brown rust (we paint/oil/galvanise to prevent it).

Worked example. Why is a cooking pot made of metal but its handle of plastic or wood?

The pot needs to carry heat to the food fast → a metal (good conductor). The handle must not burn your hand → a non-metal (an insulator). Right property for each job.

Where you'll meet it

Right material, right job

Wires & pots

Copper carries the current in your home (conductive + ductile); aluminium and steel make pots (conduct heat); plastic and wood make the handles and plug casings (insulate).

Bells & jewellery

Temple bells and cymbals are metal because they're sonorous. Gold and silver are prized for jewellery because they're lustrous and don't rust away.

Check yourself

Competency quiz

Modelled on the competency-based pattern — MCQ, assertion–reason and a case study, testing whether you can use the ideas, not just recall them.

Score 0/12

Interactive built to the OpenMAIC approach (THU-MAIC, MIT). Content from the NCERT Class 7 Science textbook, Curiosity (ncert.nic.in).

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