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Home › Grade8 › Grade 8 CBSE › Chemistry › Materials: Metals and Non-Metals › Materials: Metals and non-metals Worksheet-5

Materials: Metals and non-metals Worksheet-5

Materials: Metals and non-metals Worksheet-5

 

  1. Non-metals can not be drawn into wires. Why?

 

  1. Complete the following equation :

Zn + HCl → ___ + ___

 

  1. Give two examples of noble metals.

 

  1. Give the name of one non-metal which is a good conductor of electricity.

 

  1. Which is the most abundant metal on the earth's crust?

 

  1. Which metal can be extracted from magnetite?

 

  1. Name the ore from which aluminium is extracted.

 

  1. Why is aluminium used for making cooking utensils?

 

  1. Which of the following can be beaten into thin sheets?

(a) Zinc               (b) Phosphorus

(c) Sulphur        (d) Oxygen.

 

  1. Name the metals that occur in free state.

 

  1. Name the non-metal that occurs in  free state.

 

  1. Metals are (softer/harder) than non-metals.

 

  1. Most non-metals are (bad/good) conductors of heat.

 

  1. The property that allows the metals to be hammered into thin sheets is called (ductility/malleability).

 

  1. Melting point of most non-metals is (higher/lower) than metals.

 

  1. (Metals/non-metals) display lustre.

 

  1. The product/s formed on dissolution of magnesium oxide in water is/are _____.

 

  1. The product/s formed on burning sulphur in air is ____.

 

  1. The product/s formed on reaction between sodium and water is/are ____.

 

  1. The product/s formed on reaction between Aluminium and hydrochloric acid is/are _____.

 

Answer:

  1. Non metals exist as gas, liquid or soft solids. They are not ductile hence they cannot be drawn into wires.

 

 

  1. The noble metals are metals that are resistant to corrosion and oxidation in moist air, unlike most base metals. Few examples are Palladium, Silver, Platinum, Gold.

 

  1. Graphite is allotropic form of carbon which is good conductor of electricity.

(Explanation: The arrangement of carbon atoms in graphite is such that one electron of each carbon atom remains free which is responsible for electrical conductivity).

 

  1. Aluminium is the most abundant metal on Earth’s crust.

 

  1. Iron can be extracted from Magnetite. It is the ore of iron and consists of oxides of iron.

 

  1. Aluminium is extracted from Bauxite. Its chemical formula is Al2O3.2H2O

 

  1. Aluminium is good conductor of heat. It is also a cheap and light metal hence it is used for making cooking utensils.

 

  1. Zinc can be beaten into sheets as it is a metal.

 

  1. Metals like gold, silver, platinum, are noble metals. They occur in free state.

 

  1. Helium occurs in free state.

 

  1. Metals are harder than non-metals. Diamond an (allotrope of carbon) is an exception. It is a hard non-metal.

 

  1. Most non-metals are bad conductors of heat.

 

  1. Malleability

 

  1. Melting point of most non-metals is lower than metals.

 

  1. Metals are lustrous.

 

  1. The product formed is Magnesium hydroxide.

Chemical equation:

MgO + H2O → Mg(OH)2

 

  1. The product formed is Sulphur dioxide.

 

  1. Sodium hydroxide and hydrogen gas

2Na(s) + 2H2O(l) → 2NaOH(aq) + H2(g)

 

  1. Aluminium chloride and hydrogen gas

2Al + 6HCl → 2AlCl3 + 2H2