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2.4.1Atoms, Elements and Compounds

Conductors and Insulators — Cambridge IGCSE Chemistry 0620 Revision Notes & Topical Questions

5 min read 4 parts Lesson 23 of 26 Unit quiz

📚 Cambridge IGCSE Chemistry 0620 Hub / Topical Revision
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Curriculum Equation Key قوانين الرقم الهيدروجيني والاتزان الأيوني - pH & Acid-Base Equilibrium FormulasFast Exam Solution
pH = -log[H⁺] | pOH = -log[OH⁻] | pH + pOH = 14 | [H⁺][OH⁻] = 10⁻¹⁴
Word Equation & Conditions: الرقم الهيدروجيني = -لوغاريتم تركيز أيون الهيدروجين | pH + pOH = 14
Location & Specifications: الاتزان الأيوني، كيمياء 3 ثانوي، التحصيلي، و AP Chemistry.
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Part 1 of 4Conductors

A conductor lets charge flow through it easily, and in metals the charge carried is by electrons.

Conductor
  • Conductor A material that allows charge, usually electrons, to flow through it easily.
Metal structure
  • Metal structure A metal consists of positive metal ions in a lattice, with their outermost electrons delocalised and free to move.
Examples
  • Examples Silver, copper, aluminium and steel are good conductors because they contain many electrons that are free to move.
Link to current
  • Link to current Current is the rate of flow of charge, so the more easily electrons flow, the better the material conducts.

Part 2 of 4Insulators

Insulators
Definition
  • Definition An insulator has no free charges, so it does not allow charge to flow through it easily.
Examples
  • Examples Rubber, plastic, glass and wood are common insulators used to cover or support electrical equipment.
Limited conduction
  • Limited conduction Some non-metals such as wood conduct a little, mainly in the form of static electricity on their surfaces.
Surface charge
  • Surface charge Two insulators that touch can allow charge on their surfaces to be conducted away between them.

Part 3 of 4Conduction in Practice

1
In a copper wire, the outer electrons of each copper atom are free to drift when a potential difference is applied.
2
The drifting electrons carry charge along the wire, which is what we measure as current.
3
In an insulator such as rubber, the electrons are held tightly in their atoms, so almost no charge can move through it.
4
Metals therefore make good wires for connecting components, while plastic or rubber is used as the covering around them.

Part 4 of 4Exam Checklist & Tips

2.4.1 – Key Points for the Exam

  • Conductor A material that allows charge to flow through it easily, such as a metal.
  • Insulator A material that does not allow charge to flow through it easily because it has no free charges.
  • Delocalised electron An outer electron in a metal that is free to move through the lattice of ions.
  • Lattice A regular arrangement of ions, as found in a metal conductor.
  • Free charge A charge that is able to move through a material, such as an electron in a metal.

Common Mistakes

  • Saying metals conduct only because they contain electrons;
    • it is the delocalised electrons that are free to move.
  • Stating that insulators contain no electrons at all;
    • electrons are present but are held tightly in their atoms.
  • Describing the moving charges in a metal as positive; in metals the moving charges are electrons.
  • Claiming that current flows through insulators easily; insulators allow almost no current to flow.

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