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Metals – Non—Metals & Metalloids

Metals – Non—Metals & Metalloids

On the basis of their properties, elements can be categorised as metals, non-metals and metalloids.

Metals:

  •  An element that is malleable, ductile, and conducts electricity is called a metal.
  • Gold, silver, iron, copper, tin, lead, sodium, and uranium are some examples of metals.
  • Aluminium is the most abundant metal in the earth’s crust. Other major metals in the earth’s crust are iron, calcium, sodium, potassium and magnesium.

Important Properties of Metals | Metals – Non—Metals & Metalloids

  • Metals are malleable, e., they can be beaten into thin sheets. Gold and silver are the most malleable metals.
  • Next in the list are aluminium and copper. Silver foils are used for decorating sweets.
  • Aluminium foils are used for packing chocolates, biscuits, medicines, cigarettes, etc. Aluminium and copper sheets are used to make utensils. Iron sheets are used to make a large variety of products, like boxes, buckets, tanks, etc.
  • Metals are ductile, e., they can be drawn into thin wires.
  • Gold and silver exhibit highest ductility, followed by copper and aluminium. Copper and aluminium wires are used in electrical wiring.
  • Metals are good conductors of heat and electricity. Silver metal has been ranked as the best conductor of heat followed by copper and aluminium.
  • That is why cooking utensils are usually made of copper or aluminium.
  • Silver is the best conductor of electricity. Copper is the next best followed by gold, aluminium and tungsten.
  • Electrical wires are, therefore, made of copper and aluminium. Iron and mercury have lower electrical conductivity.
  • Metals are Gold, silver and copper have a shining surface and can be polished. They are used for making jewellery and decoration pieces.
  • On keeping in air for a long time, metals lose their shine due to the formation of a layer of oxide, sulphide or carbonate due to the action of various gases present in air.
  • Metals are hard except sodium and potassium, which are soft metals and can be cut with a knife.
  • Metals are solids at room temperature. Mercury is an exception. It is the only metal which is a liquid at room temperature.
  • Metals generally have high melting and boiling points. Exceptions are sodium and potassium which have low melting points.
  • Melting points of gallium and caesium are so low that they start melting in hand.

Non-Metals:

  • An element which is neither malleable nor ductile and does not conduct electricity is a non metal.
  • Carbon, sulphur, hydrogen, oxygen, chlorine, and iodine are some examples of non-metals.
  • Diamond and graphite are also non-metals. They are the allotropic forms of carbon.
  • Carbon is a very important non-metal because carbon compounds like proteins, fats, carbohydrates, vitamins and enzymes, etc. are essential for the growth and development of living organisms. Metals – Non—Metals & Metalloids
  • Oxygen is essential for breathing and combustion of fuels. Sulphur is present in hair, wool, onions and garlic.
  • The major non-metals in the earth’s crust in the decreasing order of their abundance are oxygen, silicon, phosphorus and sulphur.

Important Properties of Non-Metals | Metals – Non—Metals & Metalloids

  • Non-metals are They cannot be beaten into thin sheets or drawn into wires because of their brittleness.
  • Non-metals are bad conductors of heat and electricity. Many non-metals are insulators. There are a few exceptions. For example, diamond is a good conductor of heat and graphite is a good conductor of electricity. Graphite is, therefore, used for making electrodes in dry cells.
  • Non-metals are dull in appearance, i.e., they do not have lustre. Iodine is an exception. It has a shining surface like that of metals.
  • Non-metals are quite soft. Carbon in the form of diamond is an exception. In fact, diamond is the hardest natural substance known.
  • Non-metals can exist as solids (e.g., carbon, sulphur and phosphorus), liquids (e.g., bromine) and gases (e.g., hydrogen, oxygen, nitrogen and chlorine).
  • Non-metals have low melting and boiling points, except graphite which has a very high melting point.
  • Non-metals have many different colours. Sulphur is yellow, phosphorus is white or red, graphite is black, chlorine is yellowish green, bromine is reddish-brown, hydrogen and oxygen are colour less.

Metalloids:

  •  Elements which show some properties of metals and some of non-metals, i.e., properties intermediate between those of metals and non metals, are called metalloids.
  • For example, despite looking like metals, they are brittle like non-metals.
  • Instead of being good conductors of electricity like metals or insulators like non-metals, they are semi-conductors.
  • Boron, silicon and germanium are examples of metalloids. Metals – Non—Metals & Metalloids

 

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