Metals and Non-Metals: Physical and Chemical Properties of Metals and Non-Metals

Every material in our environment is made up of elements. We know of \(118\) elements, \(94\) of which occur naturally and the remaining \(24\) of which are synthetic. These elements are classed as metals, nonmetals, and metalloids based on their physical and chemical properties. In this article, you will explore the physical and chemical properties of metals and nonmetals in detail with suitable examples and reactions. You will understand what an alloy is, its uses, and the differences between metals and non-metals.

What are Metals?

The elements that conduct heat & electricity and are malleable & ductile are called metals.

Example: Copper, silver, gold, platinum, zinc, etc.

Physical Properties of Metals

Metals are generally solid except mercury which is a liquid at room temperature. These are lustrous, malleable, ductile, sonorous, hard except sodium and potassium, have high density, show high melting and boiling points except gallium and caesium, good conductors of heat and electricity.

Chemical Properties of Metals

Few chemical properties of metals are studied under the following headings: a) Reaction of metals with oxygen b) Reaction of metals with water c) Reaction of metals with dilute acids d) Reaction of metals with salt solutions e) Reaction of metals with chlorine f) Reaction of metals with hydrogen.

a) Reaction of Metals with Oxygen

Most of the metals react with oxygen \(\left( {{{\rm{O}}_2}} \right)\) in air to form metal oxides.
\({\rm{Metal}} + {\rm{Oxygen}} \to {\rm{Metal}}\,{\rm{oxide}}\)
Different metals react with oxygen at different temperatures. Some metals react with oxygen at room temperature, some react with oxygen on heating, and some react with oxygen only on strong heating.

Example 1: Sodium and potassium react with oxygen in the air at room temperature to form sodium oxide and potassium oxide, respectively.
\(4{\rm{Na}} + {{\rm{O}}_2} \to 2{\rm{N}}{{\rm{a}}_2}{\rm{O}}\)
\(4{\rm{K}} + {{\rm{O}}_2} \to 2{{\rm{K}}_2}{\rm{O}}\)
Example 2: Iron metal reacts with oxygen only at high temperature to form iron oxide. This oxide is a mixture of \({\rm{FeO}}\) and \({\rm{F}}{{\rm{e}}_2}{{\rm{O}}_3}\).
\(3{\rm{Fe}} + 2{{\rm{O}}_2} \to {\rm{F}}{{\rm{e}}_3}{{\rm{O}}_4}\)
Less reactive metals like silver, gold, and platinum do not react with oxygen even at high temperature.

Nature of Metal Oxide
The metal oxide formed is basic in nature. For example, \({\rm{N}}{{\rm{a}}_2}{\rm{O}},\,{{\rm{K}}_2}{\rm{O}},\,{\rm{MgO}}\), Cuo are basic in nature. So, these oxides turn the red litmus solution blue.
\({\rm{Metal}}\,{\rm{oxide}} + {\rm{Water}} \to {\rm{Metal}}\,{\rm{hydroxide}}\)
\({\rm{N}}{{\rm{a}}_2}{\rm{O}} + {{\rm{H}}_2}{\rm{O}} \to 2{\rm{NaOH}}\)
Whereas \({\rm{A}}{{\rm{l}}_2}{{\rm{O}}_3}\) and \({\rm{ZnO}}\) are amphoteric in nature. The metal oxide which shows acidic as well as basic properties is known as amphoteric oxide.
Example: Aluminium oxide reacts with hydrochloric acid to form aluminium chloride (salt) and water.
\({\rm{A}}{{\rm{l}}_2}{{\rm{O}}_3} + 6{\rm{HCl}} \to 2{\rm{AlC}}{{\rm{l}}_3} + 3{{\rm{H}}_2}{\rm{O}}\)
Aluminium oxide reacts with sodium hydroxide to form sodium aluminate (salt) and water.
\({\rm{A}}{{\rm{l}}_2}{{\rm{O}}_3} + 2{\rm{NaOH}} \to 2{\rm{NaAl}}{{\rm{O}}_2} + {{\rm{H}}_2}{\rm{O}}\)

b) Reaction with Water

Generally, metals react with water to produce metal oxide and hydrogen gas. Water soluble metal oxides dissolve in water to form metal hydroxide.
\({\rm{Metal}} + {\rm{Water}} \to {\rm{Metal}}\,{\rm{oxide}} + {\rm{Hydrogen}}\,{\rm{gas}}\)
\({\rm{Metal}}\,{\rm{oxide}} + {\rm{Water}} \to {\rm{Metal}}\,{\rm{hydroxide}}\)
Since the reactivity of different metals is different. Some metals react with water at room temperature, some react on heating, some react with only steam, and some do not even react with steam.
Example: Potassium and sodium react violently with cold water and form respective hydroxide. The evolved hydrogen gas immediately catches fire. This reaction is highly exothermic.
\(2{\rm{K}} + 2{{\rm{H}}_2}{\rm{O}} \to 2{\rm{KOH}} + {{\rm{H}}_2} + {\rm{Heat}}\)

c) Reaction of Metals with Dilute Acids

When a reactive metal reacts with dilute acid, a metal salt and hydrogen gas are formed.
\({\rm{Metal}} + {\rm{Dilute}}\,{\rm{acid}} \to {\rm{Metal}}\,{\rm{salt}} + {\rm{Hydrogen}}\,{\rm{gas}}\)
Example: Sodium reacts violently with dilute hydrochloric acid to form sodium chloride and hydrogen gas.
\(2{\rm{Na}} + 2{\rm{HCl}} \to 2{\rm{NaCl}} + {{\rm{H}}_2}\)
The reactivity of metal with dilute acid is as follows: \({\rm{Na}} > {\rm{Mg}} > {\rm{Al}} > {\rm{Zn}} > {\rm{Fe}} > {\rm{Cu}}\).

d) Reaction of Metals with Salt Solutions

When a more reactive metal is immersed in the salt solution of a less reactive metal, then the more reactive metal displaces the less reactive metal from its salt solution.
Suppose metal \({\rm{A}}\) is more reactive than metal \({\rm{B}}\), then metal \({\rm{A}}\) will displace metal \({\rm{B}}\) from its salt solution to form salt solution of metal \({\rm{A}}\).

\({\rm{Metal}}\,{\rm{A}} + {\rm{Salt}}\,{\rm{solution}}\,{\rm{of}}\,{\rm{metal}}\,{\rm{B}} \to {\rm{Salt}}\,{\rm{solution}}\,{\rm{of}}\,{\rm{metal}}\,{\rm{A}} + {\rm{Metal}}\,{\rm{B}}\)

Example: When the iron metal strip is dipped in copper sulphate solution, the blue colour of copper sulphate solution gradually fades and becomes light green colour, and reddish-brown copper metal is formed on the surface of the iron metal strip.
\({\rm{CuS}}{{\rm{O}}_4}({\rm{aq}}) + {\rm{Fe}} \to {\rm{FeS}}{{\rm{O}}_4}({\rm{aq}}) + {\rm{Cu}}({\rm{s}})\)

e) Reaction of Metals with Chlorine

When metals react with chlorine, it forms ionic chlorides. The metallic chloride formed is usually solid. It conducts electricity in solution or the molten state, and hence it acts as electrolytes.
\({\rm{Metal}} + {\rm{Chlorine}} \to {\rm{Metallic}}\,{\rm{chloride}}\)

Example: Calcium reacts vigorously with chlorine to form calcium chloride
\({\rm{Ca}} + {\rm{C}}{{\rm{l}}_2} \to {\rm{CaC}}{{\rm{l}}_2}\)

f) Reaction of Metals with Hydrogen

Most of the metals do not react with hydrogen, because the metals form compounds by losing electrons and hydrogen also form compounds by losing an electron. Thus, hydrogen does not accept electrons easily given by the metal to form a compound.
But few metals like sodium, potassium, calcium and magnesium undergo a reaction with hydrogen to form metal hydrides.
Example: Sodium reacts with hydrogen on heating to form sodium hydride.
\(2{\rm{Na}} + {{\rm{H}}_2} \to 2{\rm{NaH}}\)

What are Non-metals?

The elements that do not conduct heat or electricity and are neither malleable nor ductile but are brittle are called nonmetals.

Example: Carbon, phosphorus, fluorine, oxygen, etc.

Physical Properties of Non-metals

Nonmetals are generally solid or the gas except bromine which is a liquid at room temperature. These are non-lustrous except iodine, non-malleable, brittle, non-ductile, non-sonorous, comparatively soft except diamond, have low density, show low melting and boiling points except diamond, bad conductors of heat and electricity except graphite.

CLEAR YOUR CONCEPTUAL DOUBTS ON METALS & NON-METALS

Chemical Properties of Non-metals

a) Reaction of non-metals with Oxygen

Non-metals react with oxygen on heating to form oxides. These oxides may be acidic or neutral oxides. But they do not form basic oxides. The acidic oxides of non-metals dissolve in water to form acids.
Example: When carbon burns in excess of air, it forms carbon dioxide, which is an acidic oxide. This oxide dissolves in water to form carbonic acid.
\({\rm{C}} + {{\rm{O}}_2} \to {\rm{C}}{{\rm{O}}_2}\)
\({\rm{C}}{{\rm{O}}_2} + {{\rm{H}}_2}{\rm{O}} \to {{\rm{H}}_2}{\rm{C}}{{\rm{O}}_3}\)

b) Reactions of Nonmetals with Water

Usually, nonmetals do not react with water to produce hydrogen gas. This is because non-metals cannot reduce hydrogen ions of water to hydrogen gas. But a few highly reactive nonmetals such as fluorine react with water to form oxygen or ozone \(\left( {{{\rm{O}}_3}} \right)\) molecules.
\(2{{\rm{F}}_2} + 2{{\rm{H}}_2}{\rm{O}} \to 4{\rm{HF}} + {{\rm{O}}_2}\)
\(3{{\rm{F}}_2} + 3{{\rm{H}}_2}{\rm{O}} \to 6{\rm{HF}} + {{\rm{O}}_3}\)

c) Reaction of Nonmetals with Dilute Acids

Nonmetals do not react with dilute acids as they do not displace hydrogen from acids. This is because a nonmetal is an electron acceptor and so it cannot supply electrons to hydrogen ions to reduce it to hydrogen gas.

d) Reaction of Nonmetals with Salt Solutions

Generally, a more reactive nonmetal displaces less reactive nonmetal from its salt solution.
Example: When chlorine gas is passed through a solution of sodium bromide, sodium chloride, along with bromine gas is formed.
\({\rm{C}}{{\rm{l}}_2} + 2{\rm{NaBr}} \to 2{\rm{NaCl}} + {\rm{B}}{{\rm{r}}_2}\)

e) Reaction of Non-metals with Chlorine

Generally, non-metals react with chlorine to form covalent chlorides.
Example: When hydrogen reacts with chlorine in the presence of diffused sunlight, it forms hydrogen chloride gas.
\({\rm{C}}{{\rm{l}}_2} + {{\rm{H}}_2} \to 2{\rm{HCl}}\)

f) Reaction of Non-metals with Hydrogen

Generally, non-metals react with hydrogen to form covalent hydrides.
Example: When hydrogen reacts with liquid sulphur, it forms hydrogen sulphide gas at \(713{\rm{ K}}\).
\({{\rm{H}}_2} + {\rm{S}} \to {{\rm{H}}_2}\;{\rm{S}}\)

Differences between Metals and Non-metals

The differences between metals and nonmetals are explained below:

Download Metals And Non-Metals NCERT Solutions

Metalloids

Metalloids are the elements that show the properties of both metals and nonmetals.
Example: Boron \(\left( {\rm{B}} \right)\), silicon \(\left( {\rm{Si}} \right)\), germanium \(\left( {\rm{Ge}} \right)\), arsenic \(\left( {\rm{As}} \right)\), antimony \(\left( {\rm{Sb}} \right)\), tellurium \(\left( {\rm{Te}} \right)\), and astatine \(\left( {\rm{At}} \right)\).

What are Alloys?

A homogeneous mixture of two or more metals, or a metal and a nonmetal. Following are the uses of some alloys.
Example: Brass \({\rm{(Copper + Zinc)}}\), Bronze \({\rm{(Copper + Tin)}}\), German silver \({\rm{(Copper}} + {\rm{Zinc}} + {\rm{Nickel)}}\), Steel \(({\rm{Iron}} + {\rm{Carbon}})\), etc.

Metals and Non-metals Important Questions

Q.1. Give an example for metal and non-metal that exist in a liquid state.
Ans: Liquid metal is mercury \(({\rm{Hg}})\), and liquid nonmetal is bromine gas \(\left( {{\rm{B}}{{\rm{r}}_2}} \right)\).

Q.2. Define amphoteric oxide. Give an example.
Ans: The metal oxide which shows acidic as well as basic properties is known as amphoteric oxide.
Example: Aluminium oxide reacts with hydrochloric acid to form aluminum chloride (salt) and water.
\({\rm{A}}{{\rm{l}}_2}{{\rm{O}}_3} + 6{\rm{HCl}} \to 2{\rm{AlC}}{{\rm{l}}_3} + 3{{\rm{H}}_2}{\rm{O}}\)
Aluminum oxide reacts with sodium hydroxide to form sodium aluminate (salt) and water.
\({\rm{A}}{{\rm{l}}_2}{{\rm{O}}_3} + 2{\rm{NaOH}} \to 2{\rm{NaAl}}{{\rm{O}}_2} + {{\rm{H}}_2}{\rm{O}}\)

Q.3. Explain how metals react with hydrogen?
Ans: Most of the metals do not react with hydrogen, because the metals form compounds by losing electrons and hydrogen also forms compounds by losing an electron.
But few metals like sodium, potassium, calcium, and magnesium undergo a reaction with hydrogen to form metal hydrides.
Example: Sodium reacts with hydrogen gas on heating to form sodium hydride.
\(2{\rm{Na}} + {{\rm{H}}_2} \to 2{\rm{NaH}}\)

Summary

In this article, you learned about metalloids, alloys, and the difference between metals and non-metals using appropriate examples. We have discussed the basic physical properties of metals and non-metals with examples in the topic of metals and non-metals. By understanding the chemical reactions of metals and nonmetals with oxygen, water, hydrogen, chlorine, salt solution, and dilute acids, you have learned about their chemical characteristics.

PRACTICE QUESTIONS RELATED TO METALS & NON-METALS

Frequently Asked Question (FAQs) on Metals and Non-Metals

Q.1. What are the differences between metal and nonmetal?
Ans:

Q.2. What are metals and non-metals? Give examples.
Ans: The elements that conduct heat and electricity are called metals.
Examples: Iron, aluminium, copper, silver, gold, etc.
The elements that do not conduct heat or electricity are called non-metals.
Example: Oxygen, carbon, fluorine, etc.

Q.3. What are the properties of metals and non-metals?
Ans: Properties of metals: These are solid (except mercury), lustrous, sonorous, ductile, hard (except sodium and potassium), malleable, good conductors of heat and electricity, etc.
Properties of nonmetals: These are solid or gas (except bromine), non-lustrous (except iodine), non-sonorous, non-ductile, soft, non-malleable, solid nonmetals are brittle, bad conductors of heat and electricity (except graphite), etc.

Q.4. Is gold metal or non-metal?
Ans: Gold is metal because it shows the properties of metal such as lustrous nature, malleability, ductility, it is a good conductor of heat and electricity.

Q.5. Why do non-metals not react with water?
Ans: Non-metals do not react with water because non-metals cannot reduce hydrogen ions of water to hydrogen gas. Hence it can not liberate hydrogen in reaction with water.

Q.6. What are the examples of metals and non-metals?
Ans: Examples of metals are iron, aluminium, copper, silver, gold, etc.
Examples of non-metals are hydrogen, oxygen, carbon, sulphur, phosphorus, etc.

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