CBSE Class 10 Science Metals and Non Metals Assignment

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Assignment for Class 10 Science Chapter 3 Metals And Non-Metals

Class 10 Science students should refer to the following printable assignment in Pdf for Chapter 3 Metals And Non-Metals in Class 10. This test paper with questions and answers for Class 10 Science will be very useful for exams and help you to score good marks

Chapter 3 Metals And Non-Metals Class 10 Science Assignment

Question : In which of the following pair, both the substances are chemically same ?
(a) milk of lime and lime water
(b) dead burnt plaster and gypsum
(c) alumina and gypsum
(d) gypsum and plaster of paris
Answer : A

Question : Match the following -
Column ( A)                 Column (b)
(a) NaHCO3               (i) Caustic soda
(b) Na2CO3.10H2O    (ii) Baking soda
(c) NaOH                  (iii) Blue vitriol
(d) CuSO4.5H2O       (iv) Washing soda
(a) (a) (i), (b) (ii), (c) (iii), (d) (iv)
(b) (a) (ii), (b) (iv), (c) (i), (d) (iii)
(c) (a) (i), (b) (iv), (c) (ii), (d) (iii)
(d) (a) (ii), (b) (iv), (c) (iii), (d) (ii)
Answer : B

Question : Chemical (a) is used for water softening to remove temporary hardness. (a) reacts with Na2CO3 to generate caustic soda. When CO2 is bubbled through (a), it turns cloudy. What is the chemical formula of (a) ?
(a) CaCO3
(b) CaO
(c) Ca(OH)2
(d) Ca(HCO3)2
Answer : C

Question : Bleaching powder has strong bleaching action due to -
(a) chlorine
(b) nascent chlorine
(c) nascent oxygen
(d) Cl
Answer : B

Question : Dolomite is mineral whose formula is -
(a) CaCO3
(b) MgCO3
(c) CaCO3.MgCO3
(d) CaSO4.2H2O
Answer : C

Question : A solid compound ‘X’ on heating gives CO2 gas and a residue. The residue mixed with water forms ‘Y’. On passing an excess of CO2 through ‘Y’ in water, a clear solution ‘Z’ is obtained . On boiling ‘Z’. compound ‘X’ is reformed. The compound ‘X’ is -
(a) Ca(HCO3)2
(b) CaCO3
(c) Na2CO3
(d) K2CO3
Answer : B

Question : Which is not the correct process-mineral matching in metallurgical extraction.
(a) Leaching : silver
(b) Zone refining : lead.
(c) Liquation : tin
(d) Van Arkel : Zr
Answer : B

Question : Which of the following is not an ore of iron ?
(a) limonite
(b) cassiterite
(c) magnetite
(d) none of these
Answer : B

Question : In the extraction of copper from sulphide ore the metal is formed by reduction of Cu2O with :
(a) FeS
(b) CO
(c) Cu2S
(d) SO2
Answer : C

Question : Which of the following is a carbonate ore ?
(a) pyrolusite
(b) malachite
(c) diaspore
(d) cassiterite
Answer : B

Question :  Which of the following pairs will give displacement reactions?
(a) NaCl solution and copper metal
(b) MgCl2 solution and aluminium metal
(c) FeSO4 solution and silver metal
(d) AgNO3 solution and copper metal 
Answer :  D  

Question :  Metal always found in free state is? 
(a) Sodium
(b) Lithium
(c) Copper
(d) Gold
Answer :  D 
Explanation: Gold, platinum, copper, silver are few metals which can be found in free state, because they are unreactive in normal conditions with air, water and other chemicals.
 
Question :  Ayush is putting in the test tube containing water whereas Piyush is putting water in the lest tube containing . Which of the two is likely to face danger?
(a) Piyush
(b) Ayush
(c) None of the two
(d) Both Ayush and Piyush
Answer :  A
Explanation: Piyush is likely to face danger. Addition of water to concentrated sulphuric acid is an exothermic reaction and can lead to explosions. Water should not be poured into a container containing an acid. 
 
Question : Which of the following methods is suitable for preventing an iron frying pan from rusting?
(a) Applying grease
(b) Applying paint
(c) Applying a coating of zinc 
(d) All of the above
Answer :  C 
 
Question : Cryolite is used in the electrolytic reduction of Alumina (Al2O3)to: 
(a) Decrease the melting point of Al2O3
(b) All of these
(c) Act as a flux to separate gangue.
(d) To slow down the reaction.
Answer :  A 
Explanation: The difficulty of separating aluminium from oxygen in the alumina is overcome by the use of cryolite as a flux to dissolve the oxide mineral. Pure cryolite melts at 1012 °C. It dissolves the aluminium oxides sufficiently well to allow easy extraction of the aluminium by electrolysis.
 
Question : An element reacts with oxygen to give a compound with a high melting point. This compound is also soluble in water. The element is likely to be
(a) Calcium 
(b) Carbon
(c) Silicon
(d) Iron
Answer :  A 
 
Question :  Food cans are coated with tin and not with zinc because
(a) Zinc is costlier than tin.
(b) Zinc has a higher melting point than tin.
(c) Zinc is more reactive than tin. 
(d) Zinc is less reactive than tin.
Answer :  C 
 
Question : Malachite is an ore of: 
(a) Mercury
(b) Zinc
(c) Iron
(d) Copper
Answer :  D
Explanation: Malachite is a copper carbonate hydroxide mineral with the formula CuCO3.Cu(OH)2
 

Fill in the blanks :

Question. Metals can form positive ions by ……… .
Answer: losing electrons

Question. Metal reacts with water to give _____________ and hydrogen gas.
Answer: metal hydroxide

Question. The corrosion of iron is called _____________ .
Answer: rusting

Question. A non-metal which is a good conductor of electricity is ……… .
Answer: Graphite

Question. ……… is an allotroph of carbon and is the hardest natural substance.
Answer: Diamond

Question. Metals which are so soft that they can be cut with a knife are ………, ………
Answer: Sodium, Potassium

Question. A metal which burns in air with a dazzling white flame is ……… .
Answer: Magnesium

Question. Metals above hydrogen in the activity series can displace ……… from dilute acids.
Answer: Hydrogen

Question. If copper is kept open in air, it slowly loses its shining brown surface and gains a green coating. It is due to the formation of _____________ .
Answer: CuCO3

Question. _____________ is a non-metal which has a very high melting and boiling point.
Answer: Diamond

Question. Metal oxides ……… and ……… dissolve in water to form alkalis.
Answer: Sodium Oxide and Potassium oxide

Question. A non-metal which is lustrous is ……… .
Answer: Iodine

Question. The formula of calcium nitride is _____________ .
Answer: Ca3N2

 Short and Long Questions :
 
Question :   You are given a hammer, a battery, a bulb, wires and a switch.
a) How could you use them to distinguish between samples of metals and non- metals?
b) Assess the usefulness of these tests in distinguishing between metals and non- metals.
Answer : a) With the hammer, we can beat the sample and if it can be beaten into thin sheets (that is, it is malleable), then it is a metal otherwise a non-metal. Similarly, we can use the battery, bulb, wires, and a switch to set up a circuit with the sample. If the sample conducts electricity, then it is a metal otherwise a non-metal.
b) These experiments can be helpful to demonstrate the malleability and electric conductivity of the metals and non-metals.
 
Question :  What are amphoteric oxides? Give two examples of amphoteric oxides
Answer : Oxides that react with both acids and bases to form salt and water are known as amphoteric oxides.
Amphoteric oxides show properties of both acids and bases. Examples: PbO and Al2O3 . 
 
Question :   Name two metals which will displace hydrogen from dilute acids, and two metals which will not.
Answer : Zinc (Zn) and Magnesium (Mg) are the two metals which will displace Hydrogen from dilute acids as they are very reactive metals. Gold (Au) and Silver (Ag) are the metals which will not replace Hydrogen from dilute acids as these metals are less reactive. 
 
Question :   In the electrolytic refining of a metal M, what would you take as the anode, the cathode and the electrolyte?
Answer : In the process of electrolytic refining of metal called ‘M’, An impure and thick block of metal M is considered as anode, Thin strip or wire of pure metal M is taken as cathode. A suitable salt solution of metal M is considered as the electrolyte.
 
Question :  Pratyush took sulphur powder on a spatula and heated it. He collected the gas evolved by inverting a test tube over it, as shown in figure below.

8th.sci.eng.oct.nov.21.22 13

a) What will be the action of gas on:
(i) dry litmus paper?
(ii) moist litmus paper?
b) Write a balanced chemical equation for the reaction taking place.
Answer :  a) When sulphur powder is burnt in the air sulphur dioxide is formed)
(i) Sulphur dioxide does not have any effect on dry litmus paper.
(ii) Sulphur dioxide turn the moist litmus paper from blue to red because contact of SO2 with water turns to sulfurous acid 
b) S(s) + O2 (g) → SO2 (g)
SO2 (g) + H2O → H2SO3 
 
Question :   State two ways to prevent the rusting of iron.
Answer :   Iron can be prevented from rusting by:
(1) Painting.
(2) Greasing.
(3) Galvanization (Coating with zinc).
(4) By connecting with another active metal.
 
Question : What types of oxides are formed when non-metals combine with oxygen?
Answer :   When non-metals combine with oxygen it forms either acidic or neutral oxides. Ex: SO2 is an acidic oxide; CO is a neutral oxide. 
 
Question :  Give reasons:
a) Platinum, gold and silver are used to make jewellery.
Answer : Platinum, gold and silver are used to make jewellery as these metals are very less reactive hence they are not affected by air, water or most chemicals. These metals have a lot of lustre and they are malleable and ductile in nature.
 
b) Sodium, potassium and lithium are stored under oil.
Answer : Sodium and potassium are very reactive metals, if kept open these will react with oxygen and water to catch fire. Hence Sodium and potassium are kept immersed in kerosene to prevent their reaction with oxygen and moisture.
 
c) Aluminium is a highly reactive metal, yet it is used to make utensils for cooking.
Answer : This is because aluminium reacts with oxygen present in air to form a thin layer of aluminium oxide.
This oxide layer is very stable and prevents further reaction of aluminium with oxygen. Also, it is light in weight and a good conductor of heat. Hence, it is used to make cooking utensils.
 
d) Carbonate and sulphide ores are usually converted into oxides during the process of extraction
Answer : Because metals can be easily extracted from their oxides rather than from their carbonates and sulphides. 
 
Question :  You must have seen tarnished copper vessels being cleaned with lemon or tamarind juice.
Explain why these sour substances are effective in cleaning the vessels.
Answer :   Tarnished copper vessels being cleaned with lemon or tamarind because these sour substances contains acids which dissolve the layer of copper oxides and basic copper carbonate present on the surface of tarnished copper vessels. This makes them shining red-brown again. Hence they are very effective in cleaning tarnished copper vessels. 

Question : Why do ionic compound have high melting points?
Answer :  Ionic compounds do not exist as single molecules but exist as aggregates of a large number of positive And negative ions due to strong electrostatic forces. Thus, large amount of energy is required to break The inter-ionic attraction, hence these have high melting points. 

Question : Using the electronic configuration, explain how magnesium atom combines with oxygen atom to form Magnesium oxide by transfer of electrons.
Answer :  Atomic no. of magnesium = 12

Metals and Non metals_5

 

Question : What would you observe when zinc is added to a solution of iron (II) sulphate? Write the chemical Reaction that takes place.
Answer :  Zinc is more reactive than iron. When zinc is added to a solution of iron (II) suphate, green color Of iron (II) sulphate fades out and iron metal is deposited)
Zn(s) + FeSO4(aq) —–→ Fe(s) + ZnSO4(aq) 

Question : What is meant by reactivity series of metals? State which of the following chemical reaction will takes Place giving suitable reason for each.
a) Zn + CuSO4 ——→ ZnSO4 + Cu
b) Fe + ZnSO4 ——→ FeSO4 + Zn
c) Zn + FeSO3 ——→ ZnSO4 + Fe
Answer :  Reactivity series is a series of metals arranged in the order of their decreasing order of reactivity.
a) Reaction will take place because Zn is above Cu in the reactivity series and more reactive then Cu.
b) Reaction will not take place as Fe is below Zn in the reactivity series cannot displace Zn from its Solution. 

Question : Name the metal which is generally stored under kerosene and easily cut with knife.
Answer :  Sodium 

Question : Why does calcium float in water?
Answer :  It is because hydrogen gas formed which sticks to surface of calcium, therefore it floats. 

Question : Name the metal which reacts with a very dilute HNO3 to evolve hydrogen gas.
Answer :  Magnesium. 

Question : A non-metal A is the largest constituent of air, when heated with H2 in 1:3 ratio in the presence of catalyst (Fe) gives a gas B. On heating with O2 it gives an oxide C. If this oxide is passed into water in the presence Of air it gives an acid D which acts as a strong oxidizing agent.
a) Identify A, B, C and D
b) To which group of periodic table does this non-metal belongs?
Answer :  a) A = N2 Nitrogen
B = NH3Amonia
C = NO Nitrogen
D = HNO3 Nitric oxide
b) element A belongs to group 15 of the periodic table. Metal 

Question : A non-metal X exists in two different forms Y and Z. Y is hardest natural substance, whereas Z is a good conductor of electricity. Identify X, Y arid Z. 
Answer : The non-metal X is carbon (C). Y and Z are the allotropes of carbon (different physical forms of carbon). Y is diamond because diamond is the hardest natural substance known and Z is graphite which is a good conductor of electricity.
 
Question : Name two metals which will displace hydrogen from dilute acids, and two metals which will not? 
Answer : Sodium and calcium, being more reactive than hydrogen can displace hydrogen from dilute acids.
Copper and silver, being less reactive than hydrogen cannot displace hydrogen from dilute acids.
 
Question : State the property utilised in the following: 
i. Graphite in making electrodes.
ii. Electrical wires are coated with Polyvinyl Chloride (PVC) or a rubber-like material.
iii. Metal alloys are used for making bells and strings of musical instruments.
Answer : i. Graphite in an allotrope of carbon which is a good conductor of electricity because of presence of free electron and it is cheap, insoluble in water, do not react with acids and bases (non-corrosive). Due to these properties, it is used in making electrodes.
ii. Polyvinyl Chloride (PVC) or a rubber-like material are insulators means they are bad conductors of electricity and hence do not allow electrons to flow. Hence, these are used in coating the electrical wires.
iii. Metal alloys are used for making bells and strings of musical instruments because they are sonorous. 

 

Question : How will you show that silver is less reactive than copper? 
Answer : In activity series silver is placed below the copper. hence copper is more reactive than silver

a-35

The more reactive element can displace the less reactive element from its solution.
take two test tubes in test tube -1 take silver Sulphate solution(white in color) & in test tube-2 take copper Sulphate solution (blue in color). Add copper turnings to test tube -1 and add silver piece to test tube -2 keep the test tubes undisturbed for 15 minutes.
After sometime observe the color changes in both test tubes. The color in test tube – 1 changed from white to blue and there is no color change in test tube-2.this indicates in test tube-1 copper displaces silver from its silver Sulphate solution forms copper Sulphate. And in test tube- 2 no displacement reaction takes place. Hence from this experiment we are proving that copper is more reactive than silver. 
 
Question : i. Distinguish between ionic and covalent compounds under the following properties:
a. Strength of forces between constituent elements
b. Solubility of compounds in water
c. Electrical conduction in substances
ii. Explain how the following metals are obtained from their compounds by the reduction process:
a. Metal M which is in the middle of the reactivity series.
b. Metal N which is high up in the reactivity series. Give one example of each type.
Answer : i. a. Ionic compounds have strong force of attraction between the oppositely charged ions (e.g. Naand Cl-), so they are solids. Covalent compounds have weak force of attraction between their molecules, so they are usually liquids or gases.
b. Ionic compounds are soluble in water but covalent compounds are insoluble in water.
c. Ionic compounds conduct electricity when dissolved in water or when melted because they contain ions (charged particles). But, covalent compounds like glucose do not conduct electricity because they do not contain ions.
ii. a. The metal M which is in the middle of the reactivity series (such as iron, zinc, lead, copper, etc.) is moderately reactive. So, for obtaining such metals from their compounds, their sulphides and carbonates (in which they are present in nature) are first converted into their oxides by the process of roasting and calcination respectively. For example, 
a-36
 
The metal oxide (MO) are then reduced to the corresponding metals by using suitable reducing agents such as carbon. For example, zinc metal from its oxide is obtained as follow:
a-37
 
b. The metal N which is high up in the reactivity series (such as sodium, magnesium, calcium, aluminium, etc.), is very reactive and cannot be obtained from its compound by heating with carbon.
Therefore, such metals are obtained by electrolytic reduction of their molten salt. For example, sodium is obtained by the electrolysis of molten sodium chloride (NaCl).
a-38
 

Question. Generally metals react with acids to give salt and hydrogen gas. Which of the given acids does not give hydrogen gas on reacting with metals (except Mn and Mg)?
(a) H2SO4
(b) HCl
(c) HNO3
(d) All the these
Answer : C

Question. Which of the following property is generally not shown by metals?
(a) Electrical conduction
(b) Sonorous
(c) Dullness
(d) Ductility
Answer : C

Question. A reactive metal can replace a _________ reactive metal, but a _______reactive one cannot replace a ________reactive metal from its salt solution.
Fill the blanks with respectively in given order.
(a) less, more, less, more
(b) less, less, more, more
(c) more, more, less, less
(d) more, less, less, more
Answer : D

Question. Which of the following are the allotropes of carbon?
(a) Diamond and graphite
(b) Turpentine and kerosene
(c) Glass and borosilicate
(d) Fullerene and Soil
Answer : A

Question. Which among the following statements is incorrect for magnesium metal?
(a) It burns in oxygen with a dazzling white flame
(b) It reacts with cold water to form magnesium oxide and evolves hydrogen gas
(c) It reacts with hot water to form magnesium hydroxide and evolves hydrogen gas
(d) It reacts with steam to form magnesium hydroxide and evolves hydrogen gas
Answer : B

Question. An element A is soft and can be cut with a knife. This is very reactive to air and cannot be kept open in air. It reacts vigorously with water. Identify the element from the following
(a) Mg
(b) Na
(c) P
(d) Ca
Answer : B

Question. The ability of metals to be drawn into thin wire is known as
(a) ductility
(b) malleability
(c) sonorousity
(d) conducitivity
Answer : A

Question. An aluminium strip is kept immersed in a freshly prepared ferrous sulphate solution taken in a test tube, the change observed is that
(a) Green solution slowly gets decolourised with brown deposits.
(b) Lower end of the test tube becomes slightly warm
(c) A colourless gas with smell of burning sulphur is evolved
(d) Light green solution changes to blue
Answer : A

Question. Metallic oxide are generally _______in nature.
(a) Acidic
(b) Basic
(c) Neutral
(d) Amphoteric
Answer : B

Question. Aluminium is used for making cooking utensils. Which of the following properties of aluminium are responsible for the same?
(i) Good thermal conductivity
(ii) Good electrical conductivity
(iii) Ductility
(iv) High melting point
(a) (i) and (ii)
(b) (i) and (iii)
(c) (ii) and (iii)
(d) (i) and (iv)
Answer : D

Question. Which one among the following is an acidic oxide?
(a) Na2O
(b) CO
(c) CO2
(d) Al2O3
Answer : C

Question. Phosphorous is a reactive _______________and it is stored in __________
(a) Metal, water
(b) Metal, kerosene
(c) Non-metal, water
(d) Non-metal, kerosene
Answer : C

Question. Which of the following gas gives limewater test?
(a) Oxygen
(b) Nitrogen
(c) Carbon dioxide
(d) Hydrogen
Answer : C

Question : A metal M readily forms water soluble sulphate MSO4 , water insoluble hydroxide M(OH)2 and oxide MO which becomes inert on heating. The hydroxide is soluble in NaOH. The M is : 
a. Be
b. Mg
c. Ca
d. Sr
Answer : A

Question : The solubilities of carbonates decrease down the magnesium group due to a decrease in :
a. hydration energies of cations
b. inter ionic interaction
c. entropy of solution formation
d. lattice energies of solids.
Answer : A

Question : Several blocks of magnesium are fixed to the bottom of a ship to : 
a. make the ship lighter
b. prevent action of water and salt
c. prevent puncturing by under-sea rocks
d. keep away the sharks.
Answer : B

Question : One mole of magnesium nitride on the reaction with an excess of water gives :
a. one mole of ammonia
b. one mole of nitric acid
c. two moles of ammonia
d. two moles of nitric acid.
Answer : C

Question : Beryllium and aluminium exhibit many properties which are similar. But, the two elements differ in
a. exhibiting maximum covalency in compounds
b. forming polymeric hydrides
c. forming covalent halides
d. exhibiting amphoteric nature in their oxides.
Answer : A

Question : Following statements regarding the periodic trends of chemical reactivity of the alkali metals and the halogens are given. Which of these statements gives the correct picture ? 
a. The reactivity decreases in the alkali metals but increases in the halogens with increase in atomic number down the group.
b. In both the alkali metals and the halogens the chemical reactivity decreases with increase in atomic number down the group.
c. Chemical reactivity increases with increase in atomic number down the group in both the alkali metals and halogens.
d. In alkali metals the reactivity increases but in the halogens it decreases with increase in atomic number down the group.
Answer : D

Question : The ionic mobility of alkali metal ions in aqueous solution is maximum for : 
a. K+
b. Rb+
c. Li+
d. Na+
Answer : B

Question : Which one of the following orders presents the correct sequence of the increasing basic nature of the given oxides ?
a. Al2O3 < MgO < Na2O < K2O
b. MgO < K2O < Al2O3 < Na2O
c. Na2O < K2O < MgO < Al2O3
d. K2O < Na2O < Al2O3 < MgO
Answer : A

Question : The products obtained on heating LiNO3 will be : 
a. Li2O + NO2 + O2
b. Li3N + O2
c. Li2O + NO + O2
d. LiNO3 + O2
Answer : A

Question : Which of the following on thermal decomposition yields a basic as well as acidic oxide ?
a. NaNO3
b. KClO3
c. CaCO3
d. NH4NO3
Answer : C

Question : Aluminium is extracted by the electrolysis of :
a. alumina
b. bauxite
c. molten cryolite.
d. alumina mixed with molten cryolite
Answer : D

Question : Graphite is a soft solid lubricant extremely difficult to melt. The reason for this anomalous behaviour is that graphite : 
a. is a non-crystalline substance.
b. is an allotropic form of diamond.
c. has molecules of variable molecular masses like polymers.
d. has carbon atoms arranged in large plates of rings of strongly bound carbon atoms with weak interplate bonds.
Answer : D

Question : Heating an aqueous solution of aluminium chloride to dryness will give :
a. Al(OH)Cl2
b. Al2O3
c. Al2Cl6
d. AlCl3
Answer : B

Question : Refining of impure copper with zinc impurity is to be done by electrolysis using electrodes as :
Cathode Anode Cathode Anode
a. pure copper pure zinc
b. pure zinc pure copper
c. pure copper impure copper
d. pure zinc impure zinc
Answer : C

Question : Aluminium is extracted by the electrolysis of : 
a. alumina
b. bauxite
c. molten cryolite
d. alumina mixed with molten cryolite
Answer : D

Question : The metal extracted by leaching with a cyanide is :
a. Mg
b. Ag
c. Cu
d. Na
Answer : B

Question : Which one of the following ores is best concentrated by froth floatation method ? 
a. magnetite
b. cassiterite
c. galena
d. malachite.
Answer : C

Question : Heating mixture of Cu2O and Cu2S will give : 
a. Cu2SO3
b. CuO + CuS
c. Cu + SO3
d. Cu + SO2
Answer : D

Question : During the process of electro-refining of copper some metals present as impurity settle as anode mud.
These are : 
a. Sn and Ag
b. Pb and Zn
c. Ag and Au
d. Fe and Ni
Answer : C

Question : Which method of purification is represented by the following equation : 
Ti (s) + 2I2(g) →523K  TiI4(g)  →1700K  Ti (s) + 2I2(g)
a. Zone refining
b. Cupellation
c. Polling
d. Van Arkel
Answer : D

Question : In the context of the Hall - Heroult process for the extraction of Al, which of the following statements is false?
a. CO and CO2 are produced in this process 
b. Al2O3 is mixed with CaF2 which lowers the melting point of the mixture and brings conductivity
c. Al3+ is reduced at the cathode to form Al
d. Na3AlF6 serves as the electrolyte
Answer : D

Question : Which one of the following ores is best concentrated by froth floatation method?
a. Siderite
b. Galena
c. Malachite
d. Magnetite
Answer : B

Question : Roasting is a method of heating ore: 
a. In the absence of water.
b. In the presence of water.
c. In the absence of air.
d. In the presence of air.
Answer : D
Explanation: Roasting is heating of an ore in a regular supply of air in a furnace.
 
Question : The group of metals which do not react with oxygen: 
a. All of these
b. Na, Cs
c. Au, Ag
d. Pt, Cu
Answer : C 
Explanation: Gold and Silver do not react with oxygen. They are less reactive metals and lie at the bottom of the reactivity series.
 
Question : An element belonging to 16th group of periodic table is used in the manufacturing of vulcanized rubber. This element reacts with hot and conc. HNO3 to form sulphuric acid. The concerned element is: 
a. Oxygen
b. Sulphur
c. Germanium
d. Silicon
Answer : B
Explanation: The element is Sulphur. Sulphur is used to manufacture sulphuric acid and in the vulcanisation of rubber. S + 2HNO3 --> H2SO4 + 2NO
 
Question : Name the reducing agent in the following reaction: 
3MnO+ 4Al → 3Mn + 2Al2O3
a. Al2O3
b. Al
c. MnO2
d. Mn
Answer : B
Explanation: Aluminium is the reducing agent in the reaction. It reduces manganese dioxide (MnO2) to manganese (Mn) and itself gets oxidised to aluminium oxide. Manganese dioxide acts as an oxidising agent.
 
Question : Which of the following metal reacts neither with cold water nor with hot water but reacts with hot steam to produce hydrogen gas? 
a. Mg
b. Fe
c. Ca
d. Na
Answer : B
Explanation: Sodium reacts vigorously with water. Such is the reaction that it has to be stored under kerosene. Calcium can react with cold water. Magnesium reacts with hot water. Heated iron reacts with water when hot steam is passed over it.
3Fe (s) + 4H2O (g) -> Fe3O4 (s) + 4H2 (g)

Metals And Non-Metals Assertion Reason Class 10 Science  

A. Both assertion and reason are true, and reason is the correct explanation of assertion.
B. Both assertion and reason are true, but reason is not the correct explanation of assertion.
C. Assertion is true but reason is false.
D. Assertion is false and reason is true.

Question. Assertion: Copper displaces silver from silver nitrate solution.
Reason: Copper is more reactive than silver.

Answer: A

Question. Assertion: Aluminium oxide and zinc oxide are acidic in nature.
Reason: Amphoteric nature means that substance have both acidic and basic character.

Answer: C

Question. Assertion(A): Magnesium chloride is an ionic compound.
Reason (R): Metals and non-metals react by mutual transfer of electrons.

Answer: A

Question. Assertion (A): Hydrogen gas is not evolved when a metal reacts with nitric acid.
Reason (R): Nitric acid is a strong oxidising agent.

Answer: A

Question. Assertion(A): MgCl2 is a covalent compound.
Reason (R): MgClis a good conductor of electricity in molten state.

Answer: D

Question. Assertion: Electrovalency of Na is +1.
Reason: The number of electrons which an atom either loses or gains in the formation of an ionic bond is known as its valency.

Answer: B

Question. Assertion: Different metals have different reactivities with water and dilute acids.
Reason: Reactivity of a metal depends on its position in the reactivity series.

Answer: B

Question. Assertion: The oxides of sulphur and phosphorus are acidic in nature.
Reason: Metal oxides are basic in nature.

Answer: B

Question. Assertion: Iron is the most widely used metal. But it is never used in its pure state.
Reason: Pure iron is very soft and stretches easily when hot.

Answer: A


1 Mark Questions :

Question : Name the following: 

i) The most abundant metal in the earth crust.

ii) The only non-metallic element which exists as a liquid.

iii) The process by which a metallic oxide ore changes into metal.

iv) Minerals which can be profitably converted to metals.

Short Answer type Questions :

Question. The bronze medals are made up of ?
Answer: copper and tin

Question. Name some metals which may corrode easily?
Answer: Iron, copper, silver

Question. Aluminium is a highly reactive metal, yet it is used to make utensils for cooking why
Answer: Good conductor of heat

Question. What chemical process is used for obtaining a metal from its oxide?
Answer: Reduction process

Question. What are minerals?
Answer: The elements or compounds, which occur naturally in the earth‘s crust are known as minerals.

Question. Name the alloy of lead and tin
Answer: Solder

Question. Define calcination.
Answer: The process of changing the carbonate ores and its oxides by heating strongly in limited air

Question. What are ores?
Answer: Minerals from which metals can be profitably extracted are called ores.

Question. Which gas is produced when Cinnabar is heated in the presence of oxygen?
Answer: SO2

Question. Name the metals at the top of the activity series
Answer: Potassium, sodium, calcium, magnesium and aluminium

Question : Show the electronic transfer in the formation of following :

i) Sodium oxide

ii) Calcium Hydride

ii) (Magnesium chloride ( At.Nos. Na=11 , O=8 , Ca=20 , H=1 , Mg=12 , Cl=17 )

 

Question : Classify the following compounds into ionic & molecular compounds.

( Fe2O3 , CO2 , Mg3N3 , NH3 , Li2O , K3N , HCl(g) , C6H12O6 , 3 , HCl (aq), CaO )

 

Question : Give reasons: 

i) Metals can be given different shapes according to our needs.

ii) Hydrogen is not evolved when a metal reacts with nitric acid.

iii) Aluminium oxide is considered as an amphoteric oxide.

iv) Ionic compounds conduct electricity in molten state.

v) Gold and silver are used to make jewellery. 

 

Question : Swasti took sulpher powder on a spatula and heated it. He collected the gas evolved by inverting a test tube over it, as shown in the figure.

Metals and Non metals_6

(a) What will be the action of gas on
(i) Dry litmus paper?
(ii) Moist litmus paper?
(b) Write a balanced chemical equation for the reaction taking place?
Answer :  (a) (i) no action on dry litmus paper (ii) moist litmus paper becomes re as the reaction taking place.
(b) Balanced equation for the reaction taking place:
         S + O2 —-→ SO2 

Question : What is amphoteric oxide? Give examples.
Answer :  Those oxides which reacts with acids as well as bases to produce salts and water are called amphoteric Oxides. E.g. Na2O, ZnO etc. 

Question : Name two metals that do not react with water at all. 
Answer : Lead and copper.
 

Question : State reason for the following:
(i) Lemon is used for restoring the shine of tarnished copper vessels’
(ii) Copper wires are used in electrical connections.
Answer :  (i) when a copper object remains in damp air for a considerable time, the copper reacts slowly with Caron dioxide and water in air to form a green coating of basic copper carbonate on its surface. If corroded copper vessels are treated with lemon which is acidic in nature, the acid solution dissolves Green color basic copper carbonate and makes them look shiny.
(ii)Copper metal is the next best conductor of electricity after silver metal. So electric wires are made of copper.  

Question : Name a non-metal which is lustrous and a metal which is non-lustrous.
Answer :  Iodine is a non-metal which is lustrous and lead is a non-lustrous metal.  

Question : Why are metals reducing agents where as non metals are oxidizing agents? 
Answer :  Metals have a tendency to donate electrons and get oxidized. Thus, they are reducing agents. Non- metals on the other hand have a tendency to gain electrons and get reduced. Therefore, they are oxidizing agents.
 
Question : Choose from the following metals to answer the questions below: 
Aluminium, calcium, copper, iron, magnesium, potassium, nickel and zinc. Name a metal which
i. is manufactured by the electrolysis of its molten oxide.
ii. is used to galvanise iron
iii. is alloyed with zinc to make brass.
iv. reacts with aqueous copper (II) sulphate to give a pink solid.
v. does not react with cold water.
Answer :  i. The metal which is manufactured by the electrolysis of its molten oxide is Aluminium.
ii. Zinc is used to galvanise iron, because it is more reactive.
iii. Copper is alloyed with zinc to make brass.
iv. Iron reacts with aqueous copper (II) sulphate to give a pink solid.
v. Iron has no reaction with cold water but it reacts with steam.
 
Question : Why metals replace hydrogen from dilute acids, whereas non-metals do not? 
Answer : The reason why non-metals do not displace hydrogen from dilute acids is because unlike metals, non-metals do not have a tendency to lose electrons but to gain electrons. Metals have a tendency to lose electrons. These electrons, which are readily lost by reactive metals like sodium, potassium etc are accepted by hydrogen ions of the acids, reducing them to hydrogen gas (H2)
2H+ + 2e- → H2
However, non-metals do not lose electrons readily, because of which they do not displace hydrogen from acids. Another important point to note is that not all metals will displace hydrogen from acids. Only those metals which are reactive than hydrogen will displace H2 from acid.
 
Question : i. Write the electron-dot structures for sodium, oxygen and magnesium.
ii. Show the formation of Na2O and MgO by the transfer of electrons.
iii. What are the ions present in these compounds? 
Answer : 
 a-32
ii. Formation of :
The atomic number of sodium is 11 and it has only one valence electron.
Hence, electronic configuration of is 2, 8, 1.
The atomic number of oxygen is 8O and it has 6 electrons in its valence shell.
Hence, electronic configuration of is 2, 6.
Sodium has a tendency to lose the valence electron and oxygen has a tendency to gain the electron lost by sodium. Since, sodium can lose only one electron of the valence shell, and oxygen atom needs two electrons to complete its octet in the valence electron, two atoms of sodium combine with one atom of oxygen. By losing valence electron, sodium is changed into Naand by gaining two electrons lost by two sodium atoms, oxygen atom is changed into an oxide anion, . OIn this process , both the atoms, sodium and oxygen, obtain the stable electronic configuration of the noble gas neon.
 
 
a-33
It has 6 electrons in its valence shell. Therefore, it requires 2 more electrons to attain the stable electronic arrangement of neon gas. Thus, oxygen accepts 2 electrons donated by magnesium atom and forms a stable oxide ion, O2-
a-34
MgO is ionic compound.
iii. The ions present in Na2O are sodium ions (2Na+) and oxide ion O2-.
The ions present in MgO are magnesium ion (Mg2+) and oxide ion O2-.
Chapter 01 Chemical Reactions and Equations
CBSE Class 10 Science Chemical Reactions and Equations Assignment

CBSE Class 10 Science Chapter 3 Metals And Non-Metals Assignment

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