Ch. 3 Metals And Non-metals Extra Questions
Q. Which non-metal exists in liquid state?
A. Bromine
Q. What is a covalent bond?
A. A covalent bond is a bond formed by sharing of electrons between two atoms to get a stable electron arrangement. e.g. O₂, H₂O, C₂H₄ etc.
Q. What type of bonds are present in hydrogen chloride and oxygen?
A. Covalent bonds
Q. What is an ionic bond?
A. An ionic bond is a bond formed by the transfer of electrons from one atom to another. e.g. NaCl, FeSO₄, MgCl₂ etc.
Q. a) What are noble gases? What is the characteristic of the electronic configuration of noble gases?
b) What is the cause of chemical bonding (/combination) of atoms of elements?
A. a) The elements present in the group 18 of the periodic table are known as noble gases. These are the elements which are unreactive and do not react with other elements to form compounds.
The characteristic of electronic configuration of noble gases is that their octet (/duplet) is completely filled i.e. they have 8 electrons in their valence shell (or 2 in case of Helium which only has the K shell) thus making them stable and unreactive.
b) The atoms combine to complete the octet (or duplet) of their valence shell giving them an inert gas electron configuration and thus making them more stable.
Q. Give an example of a metal which
i) is a liquid at room temperature
ii) can be easily cut with a knife
iii) is the best conductor of heat
iv) is a poor conductor of heat
A. i) Mercury
ii) Sodium
iii) Silver
iv) Lead
Q. i) Which gas is produced when dilute hydrochloric acid is added to a reactive metal?
ii) Write the chemical equation when iron reacts with dilute H₂SO₄?
A. i) Hydrogen
ii) Fe(s) + H₂SO₄(aq) → FeSO₄(aq) + H₂↑
Q. Write the steps to obtain a metal from its ore in brief. What is this process called?
A. The process to obtain a metal from its ore is called extraction. Broadly, it involves 3 main steps:
i) Concentration (/Enrichment) of ore: Ore is impure as it contains a lot of unwanted material like sand and rocks called gangue. Thus it is necessary to remove these impurities to obtain the metal. This process of removing these impurities is called concentration (/enrichment) of ore.
ii) Taking out the metal from the concentrated ore: Highly reactive metals (K, Na, Ca, Mg, Al) are separated from their ore by the electrolysis of their molten chloride or oxides. Moderately reactive metals (Zn-Hg) are extracted by reducing their oxides with carbon or with a metal of higher reactivity. Some metals which occur in carbonate or sulphide forms are first converted into their oxide forms and then reduced. Less reactive metals (Ag, Au, Pt) are found in their native states. Cu and Hg are found in sulphide forms and can be extracted by simply heating them in the presence of oxygen.
iii) Refining of metals: The metals which are taken out still contain some impurities. The process of purifying impure metals is called refining. Metals are mostly refined through electrolysis i.e electrolytic refining.
Q. Define the following:
a) Malleability
b) Ductility
c) Sonority
d) Reactivity series
e) Corrosion
f) Rusting
A. a) Malleability: The property which allows metals to hammered into thin sheets is known as malleability.
b) Ductility: The property which allows metals to be drawn into thin wires is called ductility.
c) Sonority: The property of metals to produce a deep or ringing sound on being hit is called sonority.
d) Reactivity series: The vertical arrangement of metals in the decreasing order of their reactivity is called reactivity series.
e) Corrosion: The eating up of metals by the action of air, moisture or a chemical on their surface, is called corrosion.
f) Rusting: The corrosion of iron is called rusting.
4Fe(s) + 3O₂(g) ⟶ 2Fe₂O₃(s)
Q. Give reasons:
a) Metals are good conductors of heat.
a) Metals are good conductors of heat because of the presence of free electrons. When a metal is heated, its atoms gain energy and vibrate more vigorously. This energy is transferred to the electrons in the atoms.
When these free electrons move through the metal, energy is transferred to the other electrons and atoms of the metal and thus metals can conduct heat.
b) Aluminium does not react with water.
b) Aluminium doesn't react with water under ordinary circumstances because of the presence of a thin, impervious layer of aluminium oxide (Al₂O₃) on its surface.
c) Hydrogen is not evolved when metals react with dilute nitric acid.
c) Hydrogen is not evolved in a reaction between metals and dilute nitric acid because nitric acid (HNO₃) is a very strong oxidising agent. So, as soon as the hydrogen gas is formed in the reaction, the HNO₃ oxidises it to water.
d) Sodium is stored in kerosene.
d) Sodium being highly reactive, reacts vigorously oxygen. The reaction is so vigorous that sodium catches fire.
Na + O₂(/H₂O) → Na₂O + Heat +H₂
The heat evolved burns the hydrogen and thus sodium catches fire. Hence sodium is stored in kerosene.
e) Aluminium is used to make cooking utensils.
e) When Aluminium comes in contact with air, it reacts very quickly to form a thin, impervious and protective layer of aluminium oxide (Al₂O₃). This layer prevents further corrosion o aluminium making it resistant to corrosion. Moreover, aluminium being a metal, is a very good conductor heat. Hence aluminium is used for making utensils.
A. Bromine
Q. What is a covalent bond?
A. A covalent bond is a bond formed by sharing of electrons between two atoms to get a stable electron arrangement. e.g. O₂, H₂O, C₂H₄ etc.
Q. What type of bonds are present in hydrogen chloride and oxygen?
A. Covalent bonds
Q. What is an ionic bond?
A. An ionic bond is a bond formed by the transfer of electrons from one atom to another. e.g. NaCl, FeSO₄, MgCl₂ etc.
Q. a) What are noble gases? What is the characteristic of the electronic configuration of noble gases?
b) What is the cause of chemical bonding (/combination) of atoms of elements?
A. a) The elements present in the group 18 of the periodic table are known as noble gases. These are the elements which are unreactive and do not react with other elements to form compounds.
The characteristic of electronic configuration of noble gases is that their octet (/duplet) is completely filled i.e. they have 8 electrons in their valence shell (or 2 in case of Helium which only has the K shell) thus making them stable and unreactive.
b) The atoms combine to complete the octet (or duplet) of their valence shell giving them an inert gas electron configuration and thus making them more stable.
Q. Give an example of a metal which
i) is a liquid at room temperature
ii) can be easily cut with a knife
iii) is the best conductor of heat
iv) is a poor conductor of heat
A. i) Mercury
ii) Sodium
iii) Silver
iv) Lead
Q. i) Which gas is produced when dilute hydrochloric acid is added to a reactive metal?
ii) Write the chemical equation when iron reacts with dilute H₂SO₄?
A. i) Hydrogen
ii) Fe(s) + H₂SO₄(aq) → FeSO₄(aq) + H₂↑
Q. Write the steps to obtain a metal from its ore in brief. What is this process called?
A. The process to obtain a metal from its ore is called extraction. Broadly, it involves 3 main steps:
i) Concentration (/Enrichment) of ore: Ore is impure as it contains a lot of unwanted material like sand and rocks called gangue. Thus it is necessary to remove these impurities to obtain the metal. This process of removing these impurities is called concentration (/enrichment) of ore.
ii) Taking out the metal from the concentrated ore: Highly reactive metals (K, Na, Ca, Mg, Al) are separated from their ore by the electrolysis of their molten chloride or oxides. Moderately reactive metals (Zn-Hg) are extracted by reducing their oxides with carbon or with a metal of higher reactivity. Some metals which occur in carbonate or sulphide forms are first converted into their oxide forms and then reduced. Less reactive metals (Ag, Au, Pt) are found in their native states. Cu and Hg are found in sulphide forms and can be extracted by simply heating them in the presence of oxygen.
iii) Refining of metals: The metals which are taken out still contain some impurities. The process of purifying impure metals is called refining. Metals are mostly refined through electrolysis i.e electrolytic refining.
Q. Define the following:
a) Malleability
b) Ductility
c) Sonority
d) Reactivity series
e) Corrosion
f) Rusting
A. a) Malleability: The property which allows metals to hammered into thin sheets is known as malleability.
b) Ductility: The property which allows metals to be drawn into thin wires is called ductility.
c) Sonority: The property of metals to produce a deep or ringing sound on being hit is called sonority.
d) Reactivity series: The vertical arrangement of metals in the decreasing order of their reactivity is called reactivity series.
e) Corrosion: The eating up of metals by the action of air, moisture or a chemical on their surface, is called corrosion.
f) Rusting: The corrosion of iron is called rusting.
4Fe(s) + 3O₂(g) ⟶ 2Fe₂O₃(s)
Q. Give reasons:
a) Metals are good conductors of heat.
a) Metals are good conductors of heat because of the presence of free electrons. When a metal is heated, its atoms gain energy and vibrate more vigorously. This energy is transferred to the electrons in the atoms.
When these free electrons move through the metal, energy is transferred to the other electrons and atoms of the metal and thus metals can conduct heat.
b) Aluminium does not react with water.
b) Aluminium doesn't react with water under ordinary circumstances because of the presence of a thin, impervious layer of aluminium oxide (Al₂O₃) on its surface.
c) Hydrogen is not evolved when metals react with dilute nitric acid.
c) Hydrogen is not evolved in a reaction between metals and dilute nitric acid because nitric acid (HNO₃) is a very strong oxidising agent. So, as soon as the hydrogen gas is formed in the reaction, the HNO₃ oxidises it to water.
d) Sodium is stored in kerosene.
d) Sodium being highly reactive, reacts vigorously oxygen. The reaction is so vigorous that sodium catches fire.
Na + O₂(/H₂O) → Na₂O + Heat +H₂
The heat evolved burns the hydrogen and thus sodium catches fire. Hence sodium is stored in kerosene.
e) Aluminium is used to make cooking utensils.
e) When Aluminium comes in contact with air, it reacts very quickly to form a thin, impervious and protective layer of aluminium oxide (Al₂O₃). This layer prevents further corrosion o aluminium making it resistant to corrosion. Moreover, aluminium being a metal, is a very good conductor heat. Hence aluminium is used for making utensils.
Great going bro !!
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