Science - Class 8 (C ...

Q1. Fill in the blanks.

                          i.        Phosphorus is very ____________non-metal.

                         ii.        Metals are good conductors of __________and ____________.

                        iii.        Iron is ___________reactive than copper.

                        iv.        Metals react with acids to produce ___________gas.

                         v.        Most non-metals are ___________ conductors of heat.

                        vi.        Metals are __________.

          vii.        Some metals react with water to produce metal _____________and ___________gas.

          viii.        Metals can be distinguished from non-metals on the basis of their ____________and ______________properties.

                          ix.        A sample of an element contains only one kind of _______.

 

Q2. True/False

                          i.        Generally, non-metals react with acids. _______

                         ii.        Sodium is a very reactive metal. _______

                        iii.        Copper displaces zinc from zinc sulphate solution. _______

                        iv.        Coal can be drawn into wires. ________

                         v.        Metals are harder than non-metals. ________

                        vi.        Metal reacts with oxygen to form metallic oxides. ________

 

Q3. Which is more reactive iron or copper?

 

Q4. Which is less reactive sodium or gold?

 

Q5. Which one of the two is malleable oxygen or calcium?

 

Q6. Which of the two is malleable, phosphorus or iron?

 

Q7. Which metal is used to make foil to wrap food items?

 

Q8. Which metal foil is used to decorate sweets?

 

Q9. The shape of the iron nail and the aluminium wire changes on beating. Which property of metals is shown by this?

 

Q10. What is atom?

 

Q11. How many naturally occurring elements are there?

 

Q12. Why metals are said to be sonorous?

Or

Why are metals sonorous?

 

Q13. Why non-metals cannot be drawn into wires?

 

Q14. Which of the following can be beaten into thin sheets?

(a) Zinc (b) Phosphorus (c) Sulphur (d) Oxygen

 

Q15. Which of the following statements is correct?

(a) All metals are ductile.

(b) All non-metals are ductile.

(c) Generally, metals are ductile.

(d) Some non-metals are ductile.

 

Q16. Complete the following displacement reaction:

Copper sulphate + ______ -----> Zinc sulphate + ______?

 

Q17. Name the non-metal essential for our life, which all living being inhale during breathing.

 

Q18. Which of the two will produce ringing sound a metallic box or a wooden box and why?

 

Q19. There are two materials A and B. On hammering A is flattened, but B breaks. Which one is a metal?

 

Q20. Name two soft metals which can be cut with a knife.

Or

What are soft metals that can be cut with a knife?

Or

Why can sodium and potassium be cut with a knife?

Or

Which metals can be cut by a knife?

 

Q21. Give some examples of non-metals.

 

Q22. Give some examples of metals.