CONDUCTORS AND INSULATORS

CONDUCTORS AND INSULATORS

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CONDUCTORS AND INSULATORS 

The ability to conduct electricity is the major simple distinction between elements that are metals and non-metals.

Electrical Conductors

A conductor is a material that conducts electricity but is not chemically changed in the process.

They carry an electric current through freely moving electrons when a potential difference is applied across them. They include:

  • All metals (molten or solid) and the non-metal carbon (graphite). This conduction involves the movement of free or delocalized electrons (e- charged particles) and does not involve any chemical change.
  • Any molten or dissolved material in which the liquid contains free moving ions is called the electrolyte. Ions are charged particles eg Na+ sodium ion, or Cl- chloride ion, and their movement or flow constitutes an electric current, because a current is moving charged particles.

All metals and graphite are conductors of electricity.

 

Insulators

An insulator is a material that does not conduct electricity. Such materials have no free electrons.

Electrolysis

Electrolysis is the process of electrically inducing chemical changes in a conducting melt or solution eg splitting an ionic compound into the metal and non-metal.

Summary of Common Electrical Conductors

These materials carry an electric current via freely moving electrically charged particles, when a potential difference (voltage) is applied across them, and they include:

1) All metals (molten or solid) and the non-metal carbon (graphite).

This conduction involves the movement of free or delocalised electrons (e- charged particles) and does not involve any chemical change.

2) Any molten or dissolved material in which the liquid contains free moving ions is called the electrolyte. Ions are charged particles eg Na+ sodium ion, or Cl- chloride ion, and their movement or flow constitutes an electric current, because a current is moving charged particles.

The movement of opposite charges during electrolysis is due to the attracting in the electric field produced by the potential difference (the voltage).

Liquids that conduct must contain freely moving ions to carry the current and complete the circuit.

You can’t do electrolysis with an ionic solid! The ions are too tightly held by chemical bonds and can’t flow from their ordered situation! When ionically bonded substances are melted or dissolved in water the ions are free to move about.

However some covalent substances dissolve in water and form ions. eg hydrogen chloride HCl, dissolves in water to form ‘ionic’ hydrochloric acid H+Cl-(aq).

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