SCIENCE BLOG – METALS AND NONMETALS CLASS 8
INTRODUCTION
Elements are the substance which cannot be broken down into two or more simpler substances by chemical reactions. Every element is represented by a symbol. In the blog post metals and nonmetals class 8, we come to know various aspects of metals and nonmetals. There are two types of element : metals and nonmetals. Some metals are iron, aluminium, copper etc, some nonmetals are carbon, sulphur, oxygen etc. Metals can be distinguished from nonmetals on the basis of their physical and chemical properties. Properties of nonmetals are opposite to those of metal in metals and nonmetals class 8.
DIFFERENCE OF METALS AND NONMETALS CLASS 8
| CHARACTERISTICS | METALS | NONMETALS | EXCEPTION |
Malleability |
It can be beaten into thin sheets, these are malleable. | These are non-malleable, these are brittle as they break into small pieces when hammered. | ꓫ
|
Conductivity |
These are good conductors of heat and electricity like copper, silver, gold, aluminium, iron etc. | These are bad conductors of heat and electricity like carbon, sulphur, phosphorus etc. | Diamond is a nonmetal which is a good conductor of heat
Another nonmetal which conducts electricity is Graphite. |
Ductility |
It can be drawn into wires, these are ductile. | These are not ductile. When these are stretched these break into pieces and do not form wires. |
ꓫ |
Sonorousness |
It can make a metallic sound when we strike them which is called sonorous. | These are not sonorous. | ꓫ |
Lustre |
These are shiny or lustrous i.e. they have a shiny appearance. | These are not lustrous i.e. they have a dull appearance. | Iodine and Graphite are nonmetals but they have lustre. |
Hardness |
It are generally hard i.e. they cannot be cut easily. | These are mostly liquid or gaseous. But solid nonmetals are soft. | Two exceptions of soft metals are Sodium and Potassium
Diamond is a nonmetal but it is the hardest substance. |
REACTION OF METALS AND NONMETALS CLASS 8
| METALS / NONMETALS | REACTION WITH DILUTE Hydrochloric acid | REACTION WITH DILUTE Sulphuric acid |
Magnesium |
Hydrogen gas is produced
Rapid reaction |
Hydrogen gas is produced
Rapid reaction |
| Aluminium | Hydrogen gas is produced
Rapid reaction |
Hydrogen gas is produced
Rapid reaction |
Iron |
Hydrogen gas is produced.
Rapid reaction ( warm temperature) |
Hydrogen gas is produced
Rapid reaction (warm temperature) |
Copper |
No reaction (in room and warm temperature) | No reaction (in room and warm temperature) |
Charcoal (carbon) |
No reaction (in room and warm temperature) | No reaction (in room and warm temperature) |
Sulphur |
No reaction (in the room and warm temperature) | No reaction (in the room and warm temperature) |
REACTION OF METALS AND NONMETALS CLASS 8 IN ACIDS AND BASES
| BASE | METALS | ACID | NONMETALS |
| Calcium hydroxide Ca(OH)2 | CALCIUM | Sulphuric acid (H2SO4) | SULPHUR |
| Magnesium hydroxide Mg(OH)2 | MAGNESIUM | Sulphurous Acid (H2SO3) | SULPHUR |
| Sodium hydroxide NaOH | SODIUM | Nitric acid (HNO3) | NITROGEN |
| Potassium hydroxide KOH | POTASSIUM | Carbonic acid (H2CO3) | CARBON |
| Copper hydroxide Cu(OH)2CA | COPPER | Hydrochloric acid (HCl) | CHLORINE |
PROBLEMS RELATED TO METALS AND NONMETALS CLASS 8
SHORT TYPE QUESTION
Qs1 : Which metal is stored in kerosene?
Ans1 Sodium metal
Qs2 : How can you say that metals have a property of sonorousness?
Ans2 These produce sound which is sharp and high pitched. So they are called sonorous.
CONCEPTUAL QUESTIONS OF METALS AND NONMETALS CLASS 8
Qs3 Write the nature of nonmetal and metal oxide. ( reactivity series)
Ans3 Mostly nonmetallic oxides are acidic but metal oxides are basic in nature.
Qs4 Which type of materials we used for making fine electrical contacts in supercomputers and solar cells?
Ans4 We use gold and silver
GIVE REASON ON METALS AND NONMETALS CLASS 8
Qs 5 Which nonmetal is used to disinfect water?
Ans5 Chlorine has the ability to kill germs.
Qs6 Why are bells made of metals?
Ans6 Metals have sonorous property. Metal can produce a sharp and high pitched sound. So, the bells are made of metals
VERY SHORT TYPE QUESTION OF METALS AND NONMETALS CLASS 8
Qs7 State the metal which reacts with dilute hydrochloric acid to form hydrogen gas.
Ans7 Zinc.
Qs8: State the metal which does not react with dilute hydrochloric acid.
Ans8 Copper metal .
ANSWER IN BRIEF
Qs9 Which liquid metal is used for making thermometers?
Ans9 Mercury .
Qs10 What happens when a solution of metal oxide is tested with red litmus and blue litmus solutions.
Ans10 When metal oxide is tested with litmus solutions, then red litmus changes into blue colour. There is no change in the colour of blue litmus
DESCRIBE THE QUESTION METALS AND NONMETALS CLASS 8
Qs11 Out of Zinc, Iron, Copper which metal can displace from the salt solution of other two metals?
Ans11 Zinc is most reactive among three. Copper is least reactive among three. So, Zinc can displace iron and Copper from their salt solutions. Iron can displace only Copper from its salt solution. But copper cannot displace other two metals as its reactivity is the least .
Qs12 Which reacts neither with cold water nor with hot water
Ans12 Iron and zinc neither reacts with cold water nor with hot water. But these react with steam to evolve hydrogen gas.
HIGHER ORDER THINKING QUESTION OF METALS AND NONMETALS CLASS 8
Qs13: State the colour of Copper Sulphate and Ferrous Sulphate.
Ans13: Copper Sulphate is blue and Ferrous Sulphate is green colour.
Qs14 : A doctor prescribed a tablet to a patient suffering from iron deficiency. The tablet does not look like iron. Explain.
Ans14: Iron is a metal but the tablet is not made up of iron metal. Tablet is nothing but iron salt. So, it does not look like iron.
Qs15: In what form magnesium is found in plants?
Ans15: Magnesium is found in plants in the form of ionic salts in chlorophyll.
STUDY THE STATEMENT AND GIVE ANS METALS AND NONMETALS CLASS 8
Qs16: Aluminium is a metal of various uses. We use aluminium for different uses like manufacturing vehicles parts, wires of electricity, kitchen utensils and other domestic substances etc. We use this metal for iron machine welding purpose. Now, give the answer of the following questions:
- Iron and aliminium both react with oxygen. Why we take aluminium for various purposes than iron?
- Why aluminium is used in making cooking utensils?
- Give two examples where you have seen the use of aluminium foils.
EXPLAIN THE FOLLOWING IN METALS AND NONMETALS CLASS 8
Qs17: Metals are malleable and ductile. These have various useful purposes like e.g. in making coins, jewellery, electrical wires, etc. For different requirements, different metals are used. It depends on the nature of metals. Now give the answer of the following questions.
- Why do we use gold for making jewellery
- Out of Copper, Aluminium and Silver which metal is the best conductor of electricity? Justify your answer.
- Which is a good conductor of electricity, silver or copper?
- We use silver to make foil on various sweets. Is it good for health or not? If no, then in what manner in metals and nonmetals class 8?
Ans17: a) Firstly, gold is highly malleable and ductile. Secondly, air does not attack the gold.
- b) We prefer copper wire because it is the better electrical conductor than aluminium. However, silver is the best electrical conductor but it is very expensive.
- c) Silver is the better conductor of heat than copper.
- d) Yes, they are harmful for us because they affect throat and lungs