NOTES PREPARED BY
ASHAQ HUSSAIN BHAT
TEACHER SCHOOL
EDUCATION DEPARTMENT
JAMMU AND KASHMIR
MATERIALS:METALS &NON METALS
KEYWORDS
Malleability: The property of metals, by which they can be beaten into thin sheets.
Ductility: The property of metals, by which they can be drawn into wires.
Sonorous: The property of metals, by which they produce a ringing sound when stuck on a hard surface.
Conductors: The material, which allow the transport of heat or electricity easily.
Reactivity: The power of material to react with other element.
Elements: The entity, which cannot be broken down further by chemical reaction, or by cooling or by electrolysis.
Atom: The smallest unit of an element.
TEXT BOOK EXERCISES
Q.1. Which of the following can be beaten into thin sheets?
(b) Phosphorus
(d) Oxygen
(a) Zinc
(c) Sulphur
Ans. (a) Zinc
Q2. Which of the following statements is correct?
(a) All metals are ductile.
(b) All non-metals are ductile.
(c) Generally, metals are ductile.
Ans. (c) Generally, metals are ductile
Q.3. Fill in the blanks:
(a) Phosphorus is very.............. non-metal.
(b) Metals are conductor of heat and ............
(c) Iron is reactive than copper.............
(d) Metals react with acids to produce........... gas.
Ans.
(a) - reactive;
(b) - good, electricity;
(c)- more;
(d) - hydrogen
Q.4. Mark 'T' if the statement is true and 'F' if it is false.
(a) Generally, non-metals react wilh acids.
(b) Sodium is a very reactive metal.
(c) Copper displaces zinc from zinc sulphate solution.
(d) Carbon can be drawn into wires.
Ans.
(a)- False;
(b) - True;
(c) - False;
(d) - False
Q.5. Some properties are listed in the following table. Distinguish between metals and non-metals on the basis of their properties.
S. No. Properties . Metal. Non Metals
1.Appearance. Metalic Dull lusture
lusture
2.Hardness. Hard. Soft
3.Malleability. Malleable. Non Malleable
4.Ductility. Ductile. Non Ductile
5.Heat conduction. Good Conductor. Bad Conductor
6.Conduction of electricity Good Conductor. Bad Conductor (insulator)
Q.6. Give the reasons for the following:
(a). Aluminum foils are used to wrap food items.
(b) Immersion rods are made up of metallic substances.
(c) Copper cannot displace zinc from its salt solution.
(d) Sodium and potassium are stored in kerosene.
Ans.
(a) Aluminum foils are used to wrap food items because aluminium is malleable and less reactive to air and water.
(b) Immersion rods are made up of metallic substances because metals are good conductors of heat and electricity.
(c) A less reactive metal cannot replace a more reactive metal. Copper is less reactive than zinc. As a result it cannot replace zinc from its salt solution.
(d) Sodium and potassium are very reactive and they start to sodium and potassium are stored in kerosene. burn when they come in contact to air. So, to prevent burning,
Q.7. Can you store lemon pickle in aluminum utensils? Explain.
Ans. As aluminum reacts very fast with acidic solutions, so we cannot store acidic food stuffs in aluminum utensils.
Q.8. In the following table some substances are given in column I.
Ans
Column I Column II
1. Gold. Jewellery
2. Iron. Machinery
3. Aluminum. Wrapping food
4. Carbon. Fuels
5. Copper Electric Wires
6. Mercury. Thermometer
Ans. 1. (d); 2.- (e); 3. - (c); 4. - (f); 5. - (b); 6. - (a).
Q.9. What happens when:
(i) Dilute Sulphuric acid is poured on copper plate
(ii) Iron nails are placed in copper sulphate solution. Write word equations of the reactions involved.
Ans. (i) Copper sulphate is formed and hydrogen gas is liberated.
Copper + Sulphuric Acid → Copper sulphate + Hydrogen (gas)
Cu+H2SO4--------->CuSo4+H2
(ii) Brown coating is deposited on the iron nails. This is because of the displacement of copper from copper sulphate solution by iron.
Fe. + CuSo4-------->FeSo4 + Cu
Iron + Copper sulphate (sol.) → Iron Sulphate (sol.) + Copper
Q.10.Sarish took a piece of burning charcoal and collected the gas evolved in a test tube.
(i) How will she find the nature of the gas?
(ii) Write down equations of all the reactions taking place in this process.
Ans. (i) She will bring a wet litmus paper in contact with the gas. If the gas turns wet blue litmus paper into red, the gas will be acidic.
(ii) (a) Carbon +Oxygen→ Carbonic acid. (from wet litmus)
Q.11. One day Reeta went to a Jeweller's shop with her mother. Her mother gave old gold jewellery to the goldsmith to polish. Next day when they brought the jewellery back they found that there was a loss in its weight. Can you suggest a reason for the loss in weight?
Ans. Goldsmith uses acids to pure the gold jewellery, due to which some gold dissolves in the solution and hence, the weight becomes less than before.
Q.12. Why phosphorous is stored in water?
Ans. Phosphorus is a very reactive non-metal. It catches fire if exposed to air. So, to prevent the contact of phosphorus with atmospheric oxygen, it is stored in water.
ADDITIONAL SHORT ANSWER TYPE
Q.1. Why do copper utensils get greenish deposition on their surface on standing for long?
Ans. After a long standing, the copper of utensils, reacts with oxygen of air and forms its oxides, which are greenish in nature. That is why; the copper utensils get greenish deposition on their surface on long standing.
Q.2. Why is aluminium used for making cooking utensils?
Ans. Aluminium is used for making cooking utensils because of following supporting properties:
(i) It is very light in weight, so, very small heat is required to heat up the utensil.
(ii) It is good conductor of heat.
(iii) It is melleable and ductile.
(iv) It has a high tensile strength.
Q.3 Why sodium is stored in kerosene oil?
Ans:-Sodium metal is very reactive. It reacts, vigorously, with oxygen and water. A lot of heat is generated in the reaction. It is, therefore, stored in kerosene oil.
Q.4.Why is Potassium metal not stored in water?
Ans. Potassium is a reactive metal. It reacts with air, even at room temperature. Also it is a reactive metal. It reacts with water at room temperature and catches fire. Hence, it is not stored in water, but kept under kerosene oil.
2K. + 2 H₂O-------->2 KOH + H
Potassium Water Potassiumhydroxide. Hydrogen
Q.5. Explain the occurence of metals in nature.
Ans. Occurence of metals in nature. Metals occur in the nature in free, as well as, in combined state.+ H₂Hydrogen
(a) Free or native state: The metals, which are not attacked by air and moisture, generally, occur in the free or native state e.g. metals like gold, platinum etc.
(b) Combined State: Metals, generally, occur in nature in the form of compounds, such as, oxides, sulphides etc. These metals are said to occur in the combined state. e.g. aluminium oxide.
Q.6. What do you understand by ductility and malleability of a metal?
Give examples of two metals which are both ductile and malleable.
Ans. Ductility: The physical property of metals by virtue, of which metals can be drawn into thin wires is called ductility. Metals exhibiting this property are called ductile. Examples: Copper, Aluminium, Silver, Gold.
Malleability: The physical property of metals by virtue, of which metals can be beaten into thin sheets and twisted or bent without breaking are said to be malleable. Examples: Gold, Silver, Aluminium.
Examples of two metals, which are, both, malleable and ductile - Aluminium and Gold.
Q.7. Silver does not combine easily with oxygen but silver jewellery tarnishes after some time. How?
Ans. Silver does not combine, easily, with oxygen of the air, but it readily combines with sulphur compounds, such as, hydrogen sulphide present in the air to form a black coating of silver sulhphide. Therefore, silvery jewellery tarnishes after sometime.
Q.8. What is displacement reaction? Give two examples.
Ans. The reaction, in which a more reactive metal can replace a less reactive metal, but a less reactive cannot replace more reactive metals are called displacement reaction. For Example;
(i)When copper sulphate solution reacts with zinc then it displaces copper.
CuSO (Copper sulphate) + Zn(Zinc) → ZnSO, (Zinc sulphate) + Cu (Copper).
Iron displaces copper from a solution of copper sulphate forming ferrous sulphate.
CuSO4 + Fe→→ FeSO+cu
ADDITIONAL LONGANSWER TYPE QUESTIONS
Q.9. Write the difference between metals and non-metals on the basis of their physical properties.
Ans
Metals
1.Metals are good conductors of heat and electricity.
2. Metals are malleable and ductile.
3. Metals are lustrous
4. Metals are solid except mercury.
5. Metals have, generally, high melting points and boiling points.
Non-Metals
1.Non-Metals are poor conductors of heat and electricity. Metals
2. Non-Metals are neither malleable nor ductile.
3.Non metals are usually non lustrous and can not be polished
4.Non metals can exist in all states
5. Non metals generally have low melting point and boiling point
Q.10. Compare the metals and non-metals on the basis of chemical properties.
Ans
Metals
1. Metals react with oxygen to produce oxides, which are alkaline in nature.
2. Metals react with water, differently, to produce oxides and hydroxide.
3. Metals react with acid to produce hydrogen gas.
4. More reactive metals displace the less reactive metals from their compounds in an aqueous solution.
Non-Metals
1.Non-metals react with oxygen to produce oxides, which are basic in nature.
2. Non-metals do not react with water.
3. Non-metals most of times do not react with acids.
4. Non-metals do not show any such action.
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