Materials: Metals And Non-metals

The elements whose properties are intermediate between the properties of metals and nonmetals are called Metalloids. For example, Boron, Silicon and Germanium are metalloids. Heat and electricity can pass through metalloids but not as easily as in metals. Metalloids are also called semiconductors.

The metal which is liquid at room temperature is Mercury (Hg). Another metal called Gallium also exists as liquid at room temperature. Its melting point is very low and it changed into a liquid when touched.

The nonmetal which is liquid at room temperature is Bromine.

(a) The property of metals which allows metals to be hammered into thin sheets is called Malleability. Due this unique property, metals can be flattened into thin sheets by hammering and rolling.

(b) The property of metals which enables them to be drawn into wires is called Ductility. Due to this property metals can be stretched without breaking and drawn into thin wires. For example, Aluminum and copper are examples of highly ductile metals.

The two metals which are soft and easily cut with a knife are Sodium and potassium. The freshly cut surface of these metals is shiny but it tarnishes quickly on contact with air. This is because these metals react with oxygen and water and becomes dull grey in colour.

The property of metals to produce sound is called Sonority. Metals produce ringing sound and are sonorous in nature.

The property by which iron metal can be hammered to make objects of different shapes such as axe, spade etc. is called Malleability. As a result of high malleability, iron can be flattened or beaten into thin sheets and desired objects can be made by using it.

Diamond is the hardest non-metal. It is made of carbon atoms.

Carbon, in the form of Graphite is a good conductor of electricity. It conducts heat and electricity like a metal or a metalloid.

The chemical property which can be used to distinguish between a metal and a nonmetal is the formation of positive ions by metals. Metals form positive ions whereas nonmetals form negative ions. As a result, oxides of metals are basic whereas the oxides of nonmetals are acidic in nature.

Metals react with oxygen to form metallic oxides. These metallic oxides are basic because they react with water to form bases. On the other hand, nonmetals react with oxygen to form nonmetallic oxides. These oxides differ from metallic oxides because they are acidic in nature. Nonmetallic oxides react with water to form acids.

An element which forms oxide which is acidic in nature is a non-metal. This is because nonmetallic oxides react with water to form acids.

An element which forms oxide which is basic in nature is a metal. This is because metallic oxides are basic in nature and they react with water to form bases.

Metals react with oxygen in the air to produce metal oxides. For example, magnesium reacts with oxygen to produce magnesium oxide when it is heated in air:

Magnesium + oxygen → Magnesium oxide

It can also be written as:
Mg + O₂ → 2MgO

Iron is metal. It reacts with oxygen to form rust. Rust is chemically known as iron oxide. Since, rust is a metal oxide, it will be basic in nature.

Metals react with water to produce hydrogen gas. For example, sodium reacts with water to form sodium hydroxide and hydrogen gas.

Metals react with dilute acids to form metallic salts and hydrogen gas. For example, zinc reacts with dilute hydrochloric acid to form zinc chloride and hydrogen gas.

Sodium reacts vigorously with dilute hydrochloric acid because it is above hydrogen in the reactivity series of metals.

Copper does not react with dilute hydrochloric acid because it is below hydrogen in the reactivity series of metals.

Zinc is more reactive than iron. Zinc is placed above iron in the reactivity series. For example, Zinc can displace iron from ferrous sulphate solution to form zinc sulphate and iron.

Copper is less reactive than iron. For example, if we put Iron nail into copper sulphate solution. Iron nail will displace copper from copper sulphate solution.

Following are the objects in our daily life which are made of metals:

Utensils - The utensils we use daily are made from copper, aluminum and iron.

Jewellery - The jewellery is made from gold and silver.

Electric wires - These are made from copper and aluminium.

Mercury- It is used in thermometers.

Table salt- Sodium is used in making table salt.

Copper, aluminium and iron are used for making cooking utensils. Iron is used for making water boilers in factories.

Copper and aluminium are used for making electric wires due to their high ductility.

Mercury is used for making thermometers. It is liquid at room temperature and is a very good conductor of heat. Even a slightest change in temperature can be noted by using mercury.

Zinc is used to galvanize iron to protect it from rusting. In this process, a thin layer of zinc is coated on the surface of iron. Zinc acts as a barrier against corrosion so that iron does not come in contact with water or moisture in the air.

Aluminium is used to make thin foils for packaging medicines, chocolates and food items. This is because it provides a complete barrier to light, oxygen, moisture and bacteria.

Gold and silver are used to make jewellery. This is because these metals are attractive due to their luster and rarity. These metals do not tarnish or react with air.

Iron is a very important component of haemoglobin in our body. Haemoglobin is the substance in red blood cells that carries oxygen from our lungs and transports it throughout our body.

Oxygen is the nonmetal which is essential for maintaining life and is inhaled during breathing. Oxygen is brought into our lungs via breathing. It is then transported by red blood cells to the entire body to be used to produce energy.

Phosphorus is used in making fertilizers.

Chlorine is used in water purification process to make drinking water supply germ-free. Chlorine kills pathogens such as bacteria and viruses by breaking the chemical bonds in their molecules.

Iodine is used to make purple coloured solution which is applied on cuts and wounds as an antiseptic. It is used in the treatment and prevention of wound infection.

Sulphur and sodium are used in fire crackers. Fireworks contains metal salts and metal oxides which react to produce an array of colours.

Carbon is used as a fuel in the form of coke or charcoal.

(a) False

The metal which is liquid at room temperature is Mercury(Hg). Another metal called Gallium also exists as liquid at room temperature.

(b) False

Coal is made up of carbon. Carbon is a nonmetal. It is non-malleable and non-ductile; hence, coal cannot be drawn into wires.

(c) False

Metals react with dilute acids to form metallic salts and hydrogen gas. For example, zinc reacts with dilute hydrochloric acid to form zinc chloride and hydrogen gas.

(d) True

Sodium is a very reactive metal. It can even react with the moisture in the air. The reaction of sodium with water is exothermic. It produces a lot of heat.

(e) False

Copper is less reactive than zinc. It is placed below zinc in the reactivity series of metals. Hence, copper cannot displace zinc from zinc sulphate solution.

(f) True

Rust is a chemically known as iron oxide. Metal oxides are basic in nature. Since, rust is a metal oxide, it will be basic in nature.

(g) False

Metals react with water to produce hydrogen gas. For example, sodium reacts with water to form sodium hydroxide and hydrogen gas.

(a) good; electricity

Metals are used to make wires because they are good conductors of electricity. Due to good conductors of heat, metals are used to make utensils.

(b) poor

Non- metals do not have free electrons; hence, they are non-conductors of heat and electricity.

(c) reactive

Phosphorus cannot be kept open in the air because it combines with oxygen so easily that it catches fire automatically. For safety, phosphorus is stored under water in chemical laboratories.

(d) hydrogen.

Metals react with dilute acids to form metallic salts and hydrogen gas. For example, zinc reacts with dilute hydrochloric acid to form zinc chloride and hydrogen gas.

(e) reactive

Iron is more reactive than copper. For example, if we put Iron nail into copper sulphate solution. Iron nail will displace copper from copper sulphate solution.

(f) basic; acidic

Metallic oxides are basic because they react with water to form bases. Nonmetals react with oxygen to form nonmetallic oxides which are acidic in nature because they react with water to form acids.

(g) acidic; basic

Metallic oxides are basic because they react with water to form bases. Nonmetals react with oxygen to form nonmetallic oxides which are acidic in nature because they react with water to form acids.

(h) iodine

Iodine is used to make purple coloured solution which is applied on cuts and wounds as an antiseptic. It is used in the treatment and prevention of wound infection.

The two physical properties on the basis of which metals can be distinguished from non-metals are Malleability and Ductility.

The property of metals which allows metals to be hammered into thin sheets is called Malleability. Due this unique property, metals can be flattened into thin sheets by hammering and rolling.

The property of metals which enables them to be drawn into wires is called Ductility. Due to this property metals can be stretched without breaking and drawn into thin wires. For example, Aluminium and copper are examples of highly ductile metals.

When aluminium foil reacts with sodium hydroxide, sodium aluminate is formed. Metals react with dilute acids to form metallic salts and hydrogen gas. For example, Aluminium foil reacts with dilute hydrochloric acid to produce aluminium chloride and hydrogen gas.

The balanced chemical equation for the reaction is:

2Al(s) + 6HCl(aq) 2AlCl3(aq) + 3H2(g).

Aluminium is an amphoteric metal. It reacts with both acids and bases. The reaction is highly exothermic and produces a lot of heat. There is rapid evolution of hydrogen gas during this reaction.

Aluminium is highly malleable and ductile. Due to this property, aluminium is used in the production of utensils and wire. Aluminium is a good conductor of heat which makes it ideal for making utensils.

The property of metals which allows metals to be hammered into thin sheets is called Malleability. Due this unique property, metals can be flattened into thin sheets by hammering and rolling.

The property of metals which enables them to be drawn into wires is called Ductility. Due to this property metals can be stretched without breaking and drawn into thin wires. For example, Aluminium and copper are examples of highly ductile metals.

Metals have free electrons which makes them good conductors of heat and electricity. Non- metals do not have free electrons, hence, they are nonconductors of heat and electricity.

(a) Copper metal is used for making electric wires because it is highly ductile in nature. It is a good conductor of electricity.

The property of metals which enables them to be drawn into wires is called Ductility. Due to this property metals can be stretched without breaking and drawn into thin wires. Metals have free electrons which makes them good conductors of heat and electricity.

(b) Graphite is a good conductor of electricity. Graphite is made of carbon. Its valence electrons are free to move. As a result, graphite is able to conduct electricity which makes it useful for making electrode in a cell.

(c) Immersion rods for heating liquids are made of metallic substances because metallic substances are good conductors of electricity and heat. Metals have free electrons which makes them good conductors of heat and electricity.

(a) Malleability: The property of metals which allows metals to be hammered into thin sheets is called Malleability. Due this unique property, metals can be flattened into thin sheets by hammering and rolling.

(b) Ductility: The property of metals which enables them to be drawn into wires is called Ductility. Due to this property metals can be stretched without breaking and drawn into thin wires.

(i) The property of metals which allows metals to be hammered into thin sheets is called Malleability. Due this unique property, metals can be flattened into thin sheets by hammering and rolling. For example, aluminium due to its high ductility, it can be changed into thin sheets to make aluminium foil.

(ii) The property of metals which enables them to be drawn into wires is called Ductility. Due to this property metals can be stretched without breaking and drawn into thin wires. For example, Copper metal is used for making electric wires because it is highly ductile in nature.

(iii) Metals have quality to reflect light. As a result, metals are lustrous in nature. It makes metals attractive due to their luster and rarity. Hence, metals like, gold and silver are used to make jewellery. These metals do not tarnish or react with air.

(iv) Metals are sonorous because they produce a unique sound when something hard strikes their surface. As a result, metals are used in making bells or gongs.

The box made of metal can be identified by striking hard on its surface. Metals are sonorous because they produce a unique sound when something hard strikes their surface. The box which is made of metal will produce a sound on striking its surface.

Copper, gold and silver are Malleable and ductile because these are metals. The property of metals which allows metals to be hammered into thin sheets is called Malleability. Due this unique property, metals can be flattened into thin sheets by hammering and rolling. The property of metals which enables them to be drawn into wires is called Ductility. Due to this property metals can be stretched without breaking and drawn into thin wires. All of these metals can be used to make wires and sheets.

Sulphur, phosphorous and carbon are brittle. These are nonmetals and cannot be rolled into wires or drawn into sheets.

It is difficult to hold a metallic pan without a plastic or wooden handle. This is because it will result into burning of fingers or hand due to high heat. If the metallic pan has a wooden handle, it will help to hold it. Wood is made of nonmetal which is a poor conductor of heat. Hence, wooden handle is very useful in metallic pan.

Screwdriver is made of metal which is a good conductor of electricity. In order to prevent electric shocks by the screw driver its handle is made of wood. Wood is a poor conductor of electricity which protects from electric shocks and makes the screw driver safe from electric shocks.

Magnesium is a metal. Metals react with oxygen to form metallic oxides. These Hence, Magnesium oxides are basic in nature. On the other hand, nonmetals react with oxygen to form nonmetallic oxides. These oxides differ from metallic oxides because they are acidic in nature. Nonmetallic oxides react with water to form acids. Therefore, Sulphur dioxide is acidic in nature. Magnesium oxide is basic in nature.

(a) Metals react with oxygen to form metallic oxides. These metallic oxides are basic because they react with water to form bases. For example, Magnesium is a metal and magnesium oxide is basic in nature.

(b) Nonmetals react with oxygen to form nonmetallic oxides. These oxides differ from metallic oxides because they are acidic in nature. Nonmetallic oxides react with water to form acids. For example, Sulphur is a nonmetal. Sulphur dioxide is acidic in nature.

Element A is a nonmetal. Since, it is soft and brittle in nature.

Element B is a metal because it is malleable and ductile and it also conducts electricity. The property of metals which allows metals to be hammered into thin sheets is called Malleability. Due this unique property, metals can be flattened into thin sheets by hammering and rolling. The property of metals which enables them to be drawn into wires is called Ductility. Due to this property metals can be stretched without breaking and drawn into thin wires. All of these metals can be used to make wires and sheets.

(a) Carbon and Sulphur will form acidic oxides. Nonmetals react with oxygen to form nonmetallic oxides. These oxides differ from metallic oxides because they are acidic in nature. Nonmetallic oxides react with water to form acids. Therefore, oxides of sulphur and carbon i.e. sulphur dioxide and carbon dioxide are acidic in nature.

(b) Sodium and magnesium oxides will be basic in nature. Metals react with oxygen to form metallic oxides. These metallic oxides are basic because they react with water to form bases.

When copper vessel is exposed to moist air for a long time it develops a green layer on its surface. Copper corrodes by oxidation in which it reacts with oxygen in the air to form copper oxide. Copper oxide then combines with carbon dioxide to make copper carbonate, which gives it a green colour. This process is called corrosion of copper.

The green material is a mixture of copper hydroxide (Cu(OH)₂) and copper carbonate (CuCO₃). The following is the reaction

2Cu+H₂O+CO₂+O₂ → Cu (OH)₂ + CuCO₃

moist air

(a) When copper vessel is exposed to moist air for a long time it develops a green layer on its surface. Copper corrodes by oxidation in which it reacts with oxygen in the air to form copper oxide. Copper oxide then combines with carbon dioxide to make copper carbonate, which gives it a green colour. This process is called corrosion of copper. The green material is a mixture of copper hydroxide (Cu(OH)₂) and copper carbonate (CuCO₃). The following is the reaction

2Cu+H₂O+CO₂+O₂→Cu (OH)₂ + CuCO₃

moist air

(b) The green coating will be basic in nature. Green coating is made of copper oxide which is an oxide of metal. Metals react with oxygen to form metallic oxides. These metallic oxides are basic because they react with water to form bases.

(a) Metals react with water to produce hydrogen gas. Sodium reacts with water to form sodium hydroxide and hydrogen gas. Sodium is a highly reactive metal. It even reacts with the moisture present in air. The reaction of sodium with water is highly exothermic in nature. It produces a lot of heat energy and this heat energy can cause the hydrogen gas produced during the reaction, to catch fire. In order to keep it safe, sodium metal is stored in kerosene.

(b) Metals reacts with water to form metal hydroxides and hydrogen gas. These metallic hydroxides are basic. Sodium reacts with water to form sodium hydroxide and hydrogen gas. Sodium hydroxide is basic in nature.

Metals react with dilute acids to form metallic salts and hydrogen gas. For example, Aluminium foil reacts with dilute hydrochloric acid to produce aluminum chloride and hydrogen gas.

The balanced chemical equation for the reaction is:

2Al(s) + 6HCl(aq) 2AlCl₃(aq) + 3H₂(g).

When a strip of zinc is placed in copper sulphate solution it will displace copper from copper sulphate solution. Zinc is placed above copper in reactivity series of metal. Hence, it will be able to replace copper from copper sulphate solution.

Zinc + Copper Sulphate Copper + Zinc sulphate

Copper cannot displace iron from iron sulphate solution. Copper is less reactive than iron. Iron is placed above the copper in reactivity series of metals. Therefore, copper cannot displace iron from iron sulphate solution. But if we put Iron nail into copper sulphate solution. Iron nail will displace copper from copper sulphate solution.

Zinc is placed above iron in the reactivity series of metals. Hence, zinc will be able to displace iron for iron sulphate solution.

Copper cannot displace iron from iron sulphate solution. Copper is less reactive than iron. Iron is placed above the copper in reactivity series of metals. Therefore, copper cannot displace iron from iron sulphate solution.

Lemon pickle is acidic in nature. Aluminium metal is highly reactive in nature. If the pickle is stored in an aluminium container, the acid present in pickle will react with aluminium and the pickle will be spoiled.

Hence, we cannot store lemon pickle in aluminium container.

Food stuff like orange juice, pickles, chutney and curd are acidic in nature. Iron and aluminium are highly reactive metals. If any of this stuff is stored in iron or aluminium container the acid inside these food stuffs will react with iron or aluminium to produce toxins. Hence, we cannot store foodstuffs like orange juice, pickles, chutney and curd not be kept in iron or aluminium containers.

(a) Metals react with water to produce hydrogen gas. Sodium reacts with water to form sodium hydroxide and hydrogen gas. Similarly, potassium also reacts with water to potassium hydroxide and hydrogen gas. Both Sodium and potassium are highly reactive metals. They can even react with the moisture present in air. The reaction of sodium and potassium with water is highly exothermic in nature. It produces a lot of heat energy and this heat energy can cause the hydrogen gas produced during the reaction, to catch fire. In order to keep it safe, sodium and potassium are stored in kerosene.

(b) Copper cannot displace zinc from zinc sulphate solution. Zinc is placed above copper in reactivity series of metal. Hence, it will be able to replace copper from copper sulphate solution.

Zinc + Copper Sulphate Copper + Zinc sulphate

Metals are sonorous because they produce a unique sound when something hard strikes their surface. As a result, metals are used in making bells or gongs.

Metals react with water to produce hydrogen gas. Phosphorus cannot be kept open in the air because it combines with oxygen so easily that it catches fire automatically. For safety, phosphorus is stored under water in chemical laboratories.

The correct answer is (a).

Zinc is metal and it can be beaten into thin sheets. The property of metals which allows metals to be hammered into thin sheets is called Malleability.

(i) Gold - (d) Jewellery

Gold is used to make jewellery. This is because these metals are attractive due to their luster and rarity. These metals do not tarnish or react with air.

(ii) Iron - (e) Machinery

Iron is a very strong metal. It is highly malleable and ductile and hence, can be changed into desired shapes.

(iii) Aluminium - (c) Wrapping food

Aluminium is used to make thin foils for packaging medicines, chocolates and food items. This is because it provides a complete barrier to light, oxygen, moisture and bacteria.

(iv) Carbon - (f) Fuel

Carbon can be used as a fuel in the form of coke and charcoal.

(v) Copper - (b) Electric wires

The property of metals which enables them to be drawn into wires is called Ductility. Due to this property metals can be stretched without breaking and drawn into thin wires. For example, Aluminium and copper are examples of highly ductile metals.

(vi) Mercury - (a) Thermometers

Mercury is used for making thermometers. It is liquid at room temperature and is a very good conductor of heat. Even a slightest change in temperature can be noted by using mercury.

(a) Iron is used for making machinery and heavy equipment.

(b) The copper is used in making electric wires because it is a good conductor of electricity.

(c) Aluminium is used to make thin foils for packaging medicines, chocolates and food items. This is because it provides a complete barrier to light, oxygen, moisture and bacteria.

(d) Zinc is widely used in the manufacture of many products such as paints, rubber, cosmetics, pharmaceuticals, plastics, inks, soaps, batteries, textiles and electrical equipment.

(e) Mercury is used for making thermometers. It is liquid at room temperature and is a very good conductor of heat. Even a slightest change in temperature can be noted by using mercury.

(a) Oxygen is the nonmetal which is essential for maintaining life and is inhaled during breathing. Oxygen is brought into our lungs via breathing. It is then transported by red blood cells to the entire body to be used to produce energy.

(b) It can be used to replace air which helps to reduce or eliminate oxidation of materials. It is also used to make fertilizers and explosives.

(c) It is used for making fire crackers.

(d) Chlorine is used in water purification process to make drinking water supply germ-free. Chlorine kills pathogens such as bacteria and viruses by breaking the chemical bonds in their molecules.

(e) Iodine is used to make purple colored solution which is applied on cuts and wounds as an antiseptic. It is used in the treatment and prevention of wound infection.

Metals are the elements which lose electrons to form cations and are electropositive in nature. For example, Sodium, potassium, Iron, Zinc and Calcium are metals. Metals are good conductors of heat and electricity. Metals are highly malleable and ductile. The property of metals which allows metals to be hammered into thin sheets is called Malleability. Due this unique property, metals can be flattened into thin sheets by hammering and rolling. The property by which iron metal can be hammered to make objects of different shapes such as axe, spade etc. is called Malleability. As a result of high malleability, iron can be flattened or beaten into thin sheets and desired objects can be made by using it. Sodium, Potassium, Copper, Aluminium, Mercury and sodium are metals.

Nonmetals are the elements that gain electrons and form negative ions. They are also called electronegative elements. For example, chlorine, sulphur, oxygen, bromine, phosphorus and nitrogen are nonmetals. Nonmetals are not malleable and ductile but they are brittle. Nonmetals are bad conductors of heat and electricity. They have low melting and boiling points and are soft. Sulphur, Oxygen, Nitrogen, Fluorine and Chlorine are nonmetals.

The elements whose properties are intermediate between the properties of metals and nonmetals are called Metalloids. For example, Boron, Silicon and Germanium are metalloids. Heat and electricity can pass through metalloids but not as easily as in metals. Metalloids are also called semiconductors.

Metals: Metals are the elements which lose electrons to form cations and are electropositive in nature. For example, Sodium, potassium, Iron, Zinc and Calcium are metals. Metals are good conductors of heat and electricity. Metals are highly malleable and ductile.

Copper, Aluminium, Mercury and sodium are metals.

Nonmetals: Nonmetals are the elements that gain electrons and form negative ions. They are also called electronegative elements. For example, chlorine, sulphur, oxygen, bromine, phosphorus and nitrogen are nonmetals. Nonmetals are not malleable and ductile but they are brittle. Nonmetals are bad conductors of heat and electricity. They have low melting and boiling points and are soft.

Sulphur, Oxygen, Nitrogen and Chlorine are nonmetals.

Metalloids: The elements whose properties are intermediate between the properties of metals and nonmetals are called Metalloids. For example, Boron, Silicon and Germanium are metalloids. Heat and electricity can pass through metalloids but not as easily as in metals. Metalloids are also called semiconductors.

Silicon and Germanium are metalloids.

When sulphur dioxide is dissolved in water, then it forms sulphurous acid (H₂SO₃).
Explanation: Metals react with oxygen to form metallic oxides. These metallic oxides are basic in nature because they react with water to form bases. On the other hand, non-metals react with oxygen to form non-metallic oxides and these oxides differ from metallic oxides because they are acidic in nature. Also, non-metallic oxides react with water to form acids.

Sulphur is non-metal, and sulphur dioxide (SO₂) is acidic in nature. Thus, it reacts with water to form sulphurous acid (H₂SO₃ or H₂O.SO₂)

The chemical reaction is: SO₂ + H₂O → H₂SO₃

If we put Iron nail into copper sulphate solution, the iron nail will displace copper from copper sulphate solution. The following changes will be observed:

i) The colour of copper sulphate changes from blue to green after putting iron nails in it.

ii) Reddish brown colour is deposited on the iron nails. This reddish brown colour is of copper.

Because (Fe) is more reactive than copper (Cu) and is placed above copper in reactivity series of metals, thus and it changes into iron sulphate and copper.
The chemical reaction is given below:

Fe (Iron) + CuSO₄ (Copper Sulphate) → FeSO₄ (Iron Sulphate) + Cu (Copper)

Metals are the elements which lose electrons to form cations and are electropositive in nature. For example, Sodium, potassium, Iron, Zinc and Calcium are metals. Following are characteristics of metals:

1. Metals are good conductors of heat and electricity.

2. Metals are highly malleable and ductile.

3. They have very high melting and boiling points.

4. Metal oxides are basic in nature.

5. Metals displace hydrogen from dilute acids.

Nonmetals: Nonmetals are the elements that gain electrons and form negative ions. They are also called electronegative elements. For example, chlorine, sulphur, oxygen, bromine, phosphorus and nitrogen are nonmetals. Following are the characteristics of nonmetals:

1. Nonmetals are not malleable and ductile but they are brittle.

2. They are bad conductors of heat and electricity.

3. They have low melting and boiling points and are soft.

4. They form acidic or neutral oxides when they react with oxygen.

5. Nonmetals do not displace hydrogen with dilute acids.

The five uses of metals are given below:

1) Used for making machinery and heavy equipment. Ex-Iron.

2) Used in making electric wires because it is a good conductor of electricity. Ex- copper

3) Used to make thin foils for packaging medicines, chocolate, and food items. This is because it provides a complete barrier to light, oxygen, moisture, and bacteria.

4) Used in the manufacture of many products such as paints, rubber, cosmetics, pharmaceuticals, plastics, inks, soaps, batteries, textiles and electrical equipment.

5) Mercury is a liquid metal and is used for making thermometers. It is liquid at room temperature and is a very good conductor of heat.

The five uses of non-metals are given below:

1) Used for making fire crackers.

2) Oxygen is an essential non-metal for life. It helps in maintaining life and is inhaled during breathing.

3) Chlorine is used in water purification process to make drinking water supply germ-free. Chlorine kills pathogens such as bacteria and viruses by breaking the chemical bonds in their molecules.

4) Iodine is a non-metal. It is used to make purple coloured solution which is applied on cuts and wounds as an antiseptic.

5) Nitrogen is also a non-metal is used to make fertilizers and explosives.

Metals are the elements which lose electrons to form cations and are electropositive in nature. For example, Sodium, potassium, Iron, Zinc and Calcium are metals. Metals are good conductors of heat and electricity. Metals are highly malleable and ductile.

Nonmetals are the elements that gain electrons and form negative ions. They are also called electronegative elements. For example, chlorine, sulphur, oxygen, bromine, phosphorus and nitrogen are nonmetals. Nonmetals are not malleable and ductile but they are brittle. Nonmetals are bad conductors of heat and electricity. They have low melting and boiling points and are soft. Following are the difference in chemical properties between metals and nonmetals.

Potassium reacts with water to potassium hydroxide and hydrogen gas. The reaction potassium with water is highly exothermic in nature. It produces a lot of heat energy and this heat energy can cause the hydrogen gas produced during the reaction, to catch fire. In order to keep it safe potassium is stored in kerosene.

Silver is less reactive than zinc, copper and magnesium. It is below all these metals in the reactivity series of metals.

Sulphur is a nonmetal. It cannot be drawn into wires or changed into sheets. It is very soft and hence, is brittle in nature.

Phenolphthalein is an indicator used in acid-base titrations. It turns colorless in acidic solutions and pink in basic solutions. Sodium is a metal which reacts with water to form sodium hydroxide, which is a base. Hence, phenolphthalein turns the solution pink.

Bromine is the nonmetal which is a red-brown liquid at room temperature. It evaporates readily to form a similarly coloured gas.

Potassium is a metal. Metallic oxides are basic in nature.

The property of metals which allows metals to be hammered into thin sheets is called Malleability. Due this unique property, metals can be flattened into thin sheets by hammering and rolling.

Silver is least reactive will not produce hydrogen gas with sulphuric acid.

Sodium is stored in kerosene because it is highly reactive and it even reacts with moisture from air and catches fire.

Zinc sulphate solution and calcium cannot undergo displacement reaction.

This is because zinc is more reactive than iron. Hence, iron cannot displace zinc from zinc sulphate solution.

Mercury is used for making thermometers. It is liquid at room temperature and is a very good conductor of heat.

Carbon is a nonmetal. Nonmetals form oxides which are acidic in nature. Oxide of carbon is acidic and hence, its aqueous solution will turn blue litmus to red.

Silicon is a metalloid. The elements whose properties are intermediate between the properties of metals and nonmetals are called Metalloids.

Carbon is a nonmetal. Nonmetals form oxides which are acidic in nature. Oxide of carbon is acidic.

Silver is least reactive and is placed below all these metals in reactivity series of metals.

Copper cannot displace iron from iron sulphate solution because copper is less reactive than iron.

Copper corrodes by oxidation in which it reacts with oxygen in the air to form copper oxide. Copper oxide then combines with carbon dioxide to make copper carbonate, which gives it a green colour. This process is called corrosion of copper.

Calcium is the most reactive metal than copper, iron and magnesium. It lies above all of these metals in reactivity series.

Metals react with oxygen to form metallic oxides. These metallic oxides are basic because they react with water to form bases. Sodium is a metal, its oxide will be basic in nature and it will turn red litmus solution to blue.

Brittleness is not a characteristic property of Iron because it is a metal. Malleability, ductility, and sonorousness are the properties of metals.

(a) This reaction will not occur. Zinc is more reactive than copper. Copper will not be able to replace zinc from zinc sulphate solution. A more reactive metal can replace a less reactive metal, but a less reactive one cannot replace a more reactive metal. On the other hand, if we take copper sulphate solution and zinc, then zinc will be able to replace copper from copper sulphate solution. Hence, the above reaction will not take place.

(b) A more reactive metal can replace a less reactive metal, but a less reactive one cannot replace a more reactive metal. This reaction will take place. In this case, Iron is more reactive than copper. In a solution of copper sulphate, iron will react and will be able to displace copper from its solution. In this reaction, iron will change into iron sulphate and copper metal will be produced.

When gold jewellery is sent for polishing, it loses weight. While polishing, the outer thin layer of gold which is dull is removed by treatment with a chemical. The chemical treatment of this layer causes a reduction in weight of gold ornaments. This leads to a slight loss in the weight of jewellery.

The aqueous solution of the oxide turns blue litmus paper red. This means the aqueous solution is acidic in nature. Metals react with oxygen to form metallic oxides. These metallic oxides are basic because they react with water to form bases. On the other hand, nonmetals react with oxygen to form nonmetallic oxides. These oxides are different from metallic oxides because they are acidic in nature. Nonmetallic oxides react with water to form acids. Since, the aqueous solution of this oxide is acidic in nature, the element is a nonmetal. For example, Sulphur is a nonmetal. It will form an oxide called sulphur dioxide which is acidic in nature.

Turmeric is used as a natural indicator. Turmeric is yellow in colour. Turmeric paper turns into red when it is dipped into basic solution. Turmeric paper does not change its colour with acid. The aqueous solution of this oxide turns turmeric paper red. It indicates that the oxide is basic in nature. Metals react with oxygen to form metallic oxides. These metallic oxides are basic because they react with water to form bases. On the other hand, nonmetals react with oxygen to form nonmetallic oxides. These oxides are different from metallic oxides because they are acidic in nature. Nonmetallic oxides react with water to form acids. Hence, the element is a metal. For example, magnesium is a metal, it reacts with oxygen to magnesium oxide, which is basic in nature.

(a) The ‘pop’ sound indicates the presence of hydrogen gas. Metals react with dilute acids to form metallic salts and hydrogen gas. Some metals react with bases to produce hydrogen gas. Generally, non-metals do not react with acids. For example, Aluminium reacts with dilute hydrochloric acid to form Aluminium chloride and hydrogen gas. The balanced chemical equation for the reaction is:

2Al(s) + 6HCl(aq) 2AlCl₃(aq) + 3H₂(g).

Aluminium is an amphoteric metal. It reacts with both acids and bases. The reaction is highly exothermic and produces a lot of heat. There is rapid evolution of hydrogen gas during this reaction. Aluminium metal reacts with a base called sodium hydroxide to produce sodium aluminate and hydrogen gas.

(b) The name of the gas is hydrogen.