10th Class Science Metals and Non-metals

Metals and Non-metals

Category : 10th Class

 Metals and Non- Metals

 

  • Metals and non-metals: On the basis of properties, all the elements can be divided into two main groups: metals and non-metals.

 

  • Sodium, Potassium, Calcium and Magnesium form positive ions. A majority of the known elements are metals. All metals are solids, except mercury which is a liquid metal.

 

  • The most abundant metal in the earth's crust is aluminium.

 

  • Though non-metals are small in number as compared to metals, they play a very important role in our daily life.

 

  • The most abundant non-metal in the earth's crust is oxygen.

 

  • Metallurgy: Metallurgy is the branch of chemistry that deals with the extraction of metals from their ores.

 

  • Physical Processes involves crushing, grinding and concentration of the ore, gravity separation, froth floatation and electromagnetic separation.

 

  • Chemical Processes involve roasting, calcination, reduction of metallic oxide to free metal, reduction of ore and refining of metals.

 

  • Refining of metals: Metals obtained by the above processes contain impurities such as presence of other metals, non-metals like silicon or phosphorus, unreduced oxides and sulphides of the metal. Following processes involve refining of various metals:

 

(i) Liquidation: This method is used to refine metals having a low melting point, e.g., lead and tin.

(ii) Distillation: Used to refine volatile metals like mercury and zinc which contain non volatile impurities.

(iii) Oxidation: Used to refine metals containing volatile impurities, which are easily oxidised, e.g., pig iron.

(iv) Electro - refining: This is an economical and effective method for purifying metals, e.g., copper, aluminium, lead.

 

  • Reactivity series (or activity series) of metals

Other Topics

Notes - Metals and Non-metals
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