CCE :Class VIII :Metal and Non Metal : Fill in the blanks

CCE :Class VIII :Metal and Non Metal : Fill in the blanks

1. ---------- is liquid  metal

(mercury)

2. ------ , -------------- and     ----------- are soft metal

(Lithium, Potassium, Sodium)

3.    ------------ and  ------------ are have low melting points. They melt in the palm of the hand

(Gallium and Ceasium)

4. Metals can be beaten into thin sheets so they are called     ----------------

(malleable)

5. ---------- is only liquid Non metals

(Bromine)

6.  -------------- is the hardest natural substance

(diamond)

7. Non metals are bad conductors of electricity  except -------------

(graphite)

8. Metals react with oxygen to form ---------- oxides (Basic)

9. Some metal oxides show acidic and basic properties. They are called ---------. Eg :- Aluminum oxide, Zinc oxide etc.

(amphoteric oxides)

10. Al2O3  +  6HCl    ------à ----------  +  3H2O

(AlCl3)

11.    Al2O3  +  NaOH     -------à --------    +  H2O

(NaAlO2)

12. -------------- and  ---------does not react with oxygen even at high temperature.

( Silver, gold)

13. Metals like potassium and sodium react vigorously with oxygen and catch fire if kept in open. Hence they are stored in ------------ to prevent burning.

(kerosene)

14. Magnesium reacts only with ---------- water to form magnesium hydroxide and hydrogen.

( hot)

15. Metals like aluminium, iron and zinc react only with  ----  to form the metal oxides and hydrogen. (steam)

16.  --------  gas is not evolved when metals react with nitric acid (HNO3) because it is a strong oxidising agent

(Hydrogen)

17. A more reactive metal displaces a ------- reactive metal from its salt solution

(less)

18. The arranging of metals in the decreasing order of their reactivity is called  -----------series of metals.

( reactivity)

19. Metals lose electrons and become positive ions. So they are called ------elements

(electropositive)

20. Non metals ----- electrons and become negative ions. So they are called electro negative elements

(gain)

21. ----------are compounds formed by the transfer of electrons from a metal to a non metal(Ionic compounds)

22. If one of the metals in an alloy is mercury, it is called an  -------

( amalgam)

23. ---------is the damage caused to metals due to the reaction of metals with oxygen, moisture, carbon dioxide etc.

(Corrosion)

24. Some elements show properties of both metals and non metals. They are called -----

(metalloids)

25. -------------is a mixture of concentrated nitric acid and concentrated hydrochloric acid in the ratio 1:3.

( Aqua regia)