1. What are called metalloids? Give Example.

The elements which possess both the properties of metals as well as non metals are called metalloids.They contain one kind of atoms . Example: Silicon, Germanium and Antimony

2. Write the physical properties of metals?   

    (a)  All the metals are solid at room temperature. Exception for this is mercury and gallium which are liquid at room temperature
    (b)  Metals have lusture quality
    (c)  All metals possess malleability
    (d)  Metals possess  ductility
    (e)  Metals are good conductor of heat and have high melting point.
    (f)   Metals are good conductor of electricity
    (g)  Metals are generally hard
    (h)  Metals usually have high melting and boiling point
    (i)  The metals produce sound on striking a hard surface.

3. What is known as lusture property of a metal?

Metals in their pure state have a shine and can be polished to give a high quality reflective surface. This property of metal is called a lusture.

4. What is called malleability of metals?

Metals have the ability to withstand hammering and can be made into these sheets. This property is called malleability of metals.

5. What is called the ductility of metals?    

The ability of the metals to be drawn in to thin wires is called the ductility of metals.

6. Why the bells in the schools, temples and churches made of metals?  

The metals can produce a sound while striking the hard surface, due to this property of metals; we are using them for making bells.

7.  What are the physical properties of non metals?

      a.    Non metals are either in solid or gaseous state
     b.    Non metals don’t possess lusture.
     c.    Non metals don’t possess the property of hardness. They are not malleable or ductile .
    d.    Non metals do not conduct electricity.

8.  What are the chemical properties of metals?
    
     a) Metals reacts with oxygen to produce their oxides.

       Example : Sodium reacts with oxygen to produce sodiumoxide .

                        4Na + O₂  _______>2Na₂O

      b) Metals react with  water to produce their hydroxides.

         Example   :   Sodium reacts with water to produce sodiumhydroxide and hydrogen .

                               2Na  +2H₂O  ________>  2NaOH  +H₂
     c)   Metals react with acids to produce salt and hydrogen gas.

       Example  :  Sodium reacts with hydrochloricacid to produce sodiumchloride and hydrogen.

           2Na +2HCl  __________>  2NaCl  +H₂

9.  Write the formula of metals react with oxygen?

Sodium and potassium reacts with oxygen at room temperature to produce their oxides.
      4Na+O₂ →2Na₂ O
Magnesium not reacts with oxygen at room temperature but on heating it burns in air with intense light and heat to form magnesium oxide
      2Mg+O₂  →2MgO
Zinc in air on strong heating to form zinc oxide
      2Zn+O₂ →2ZnO

10.  Why sodium is kept under kerosene oil?

Sodium is highly reactive metal even at room temperature in order to prevent its reaction with oxygen, moisture and carbon dioxide; it is kept under kerosene oil.

11. Give an example to the statement that metal oxides are soluble in water?

Sodium and potassium reacts with air to produce their oxides. These oxides are soluble in water to produce alkalis which are basic in nature. The formula of this reaction is
   
    4Na+O₂→2Na₂O
    Na₂O+H₂O→2NaOH
    4K+O₂→2K₂O
    K₂O+H₂O→2KOH

12. What is known as anodizing?

Anodizing is a process of forming the thick oxide layer of aluminium. Aluminium develops a thick oxide layer when exposed to air. This layer is used as resistant to metal metal from further corrosion

13. What are known as amphoteric oxides?      

Some metal oxides such as aluminium oxides and zinc oxides react with acids as well as bases to produce salt and water. These are known as amphoteric oxides.

14. Write the chemical formula for amphoteric reaction?

     Al₂O₃+6HCl→2AlCl₃+3H₂O
     Al₂O₃ + 2NAOH→ 2NaAlO₂+H₂

15. What is known as exothermic reaction? Give an Example?

 Some metals react with cold water producing a large amount of heat along with hydrogen. This reaction is known as exothermic reaction.  
     Eg: 2K+2H₂O→2KOH+H₂+Heat

16. Why all the metals does not evolve hydrogen gas while reacting with nitric acid?       

Nitric acid is a strong oxidizing agent, it oxidizes the hydrogen to water and itself gets reduced to any of nitrogen oxides. So it does not evolve hydrogen gas.

17. What is known as displacement reaction?

When a metal reacts with a solution of other metal salts, it displaces the metal which is less reactive than other one. This reaction is known as displacement reaction.

18. Give an example for displacement reaction?

An iron nail reacts with copper sulphate solution, the iron nail gets coated with a reddish brown color of copper and the blue color of copper sulphate solution is fades out. In this reaction more reactive iron has displaces copper with less reactive from the copper sulphate solution. This reaction is an example for displacement reaction.

19. Why noble gases are not reactive? (or why noble gases are chemically inactive?)

The noble gases have a completely filled valence shell thus they are chemically inactive or not reactive towards other elements.

20. Why chlorine is used in making chemical weapon?

Chlorine is  a very  poisonous metal and when chlorine and sodium are chemically bonded together these two becomes dangerous sulphate forms . That is why chlorine is used in chemical weapons.

21. What is known as equivalent bonds or ionic bonds?

The compounds by giving and taking electrons from a metal to non metals are known as ionic compounds or equivalent compounds.

22. What is called a covalent bond?

The chemical compound that is formed by metal sharing of one or more pairs of electrons between the two combining atoms are called covalent compound. Example Ammonia, Water.

23. Why Gold is formed in the nature as its free states?    

Because the metals like gold, silver and platinum are very less reactive in  nature. So these are found in free of state.

24. What is known as minerals?   

The reactive metals are found in combined state in the form of their oxides ores and carbonate ores. These naturally occurring compounds of metals along with other impurities are known as minerals.

25. What is known as ores?

Minerals from which metals are extracted profitably and conventionally are called ores. It contains metal compounds with some of the impurities like oil, sand, rocky materials etc.