Name: Electrical Conductivity of Metals and Non-metals
Uploaded: 2019-07-19
Duration: 4 min 50 s
Description: Materials that allow an electric current to pass through them are the conductors of electricity. This video helps to understand the concept of electrical con...

Question

Write the important physical properties of metals and mention the exceptions, if any.

Accepted Answer

The physical properties of metals are as follows:
Nature of the metals: All metals are crystalline solid at room temperature except mercury, which is a liquid at room temperature.

Metallic lustre: Metals in their pure state, have a shiny surface and show metallic lustre. Example: $Cu$ , $Ag$ , $Au$ , $Mg$ , $Al$ etc.

Density: Metals usually have high densities. However, certain metals for example alkali metals and alkaline earth metals like lithium, sodium, potassium, beryllium and magnesium etc. have very low densities.

Melting and Boiling points: Most metals have high melting and boiling points. Sodium, potassium, mercury, gallium and caesium are exceptions and possess very low melting points. The melting points of gallium and caesium are so low that they melt on keeping them over the palm.

Malleability and Ductility:
The property of metals to form thin sheets on beating by a hammer is called malleability. For example: Silver, gold and Aluminium etc.
The property of metals to be drawn Into thin wires is called ductility.
Example: Copper, Zinc etc.

Hardness: Metals are usually hard and hardness differs from metal to metal. Some metals such as sodium, potassium (alkali metals), lead etc. are quite soft and can be cut with a knife. Tungsten. Iron, copper etc. are quite hard and cannot be cut with a knife.

Tensile strength: The property of a metal to hold strain without breaking is called its tensile strength.
Iron possesses a very high tensile strength and is largely used in the construction of girders, rails, machines, buildings, bridges etc.

Electrical conduction: Metals are good conductors of electricity, i.e., they allow the electric current to pass through them. Because they have low resistivity. Example: Silver, copper, gold and aluminium etc.

Thermal conductivity: Metals are also good conductors of heat, i.e., they allow the passage of heat through them because of the free electrons.

Alloy formation: Metals with other metals or non-metals can be mixed together in the molten state. The molten mixture on cooling gives a solid solution called an alloy.
Some important alloys are brass, German silver, bronze, stainless steel etc.

Sonorous nature: The property of a metal to produce a deep sound on being hit with an object is called sonority or sonorousness.
The bells, strings of musical instruments etc., are made of metals due to their sonorous nature.

Allotropy: The property of elements to exist in more than one form is called allotropy. Example: Tin ( $Sn$ ), a metal that exists in two forms: $Sn$ grey and $Sn$ white.

Write the important physical properties of metals and mention the exceptions, if any.

Important Questions on Metals and Non-metals

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