Metals and Non-Metals – Quick Revision Notes (Class 10)

Metals and Non-metals – quick revision notes is an important topic for students preparing for RBSE Class 10 examination. This chapter is based on NCERT syllabus explains the physical and chemical properties of metals and non-metals, their reactions and used in everyday life.

For RBSE Class 10 Science Students, mastering this chapter is essential for scoring god marks in exams. After reading these notes, you can solve questions of the chapter and practice with MCQs for better understanding.

Introduction

Elements are broadly classified into metals and non-metals based on their physical and chemical properties. The properties of these elements determine their used in daily life.

Understanding the properties and reactions of metals and non-metals is important for explain many natural processes and industrial applications.

Physical Properties of Metals

Metallic lustre

Metals in their pure state usually have a shiny surface, known as metallic lustre. When metals are freshly cut or cleaned by rubbing with sandpaper, they show a bright appearance.

Example: gold, silver, copper

Malleability

Malleability is the property of metals by which they can be hammered or beaten into thin sheets without breaking.

Examples: Aluminium foil, gold and silver sheets

Gold and silver are among the most malleable metals.

Ductility

Ductility is the ability of a metal to be drawn into thin wires.

Examples: Copper and aluminium wires are used in electrical wiring.

Gold is the most ductile metal. A wire of about 2 km length can be drawn from 1 gram of gold.

Hardness

Most metals are hard substance, but hardness varies from metal to metal.

Examples: Iron is hard but sodium and potassium are soft metals

Conduction of Heat

Metals are good conductors of heat. This property makes them useful in cooking utensils.

Best conductors of heat: Silver and copper

Poor conductors of heat: Mercury and lead

Conduction of Electricity

Metals allow the flow of electric current because they contain free electrons.

Examples: Copper and aluminium are used in electrical wires.

Sonority

Metals produce a ringing sound when struck with a hard object. This property is called sonority.

Examples: School bells are made of metals

High melting and boiling points

Most metals have high melting and boiling points due to strong attraction force between particles. So they are used in machines, tools and cookware.

Physical Properties of Non-Metals

Non-metals have properties opposite to metals.

Non-metals are/have

                      i.   Usually dull (non-lustrous)

                   ii.    Brittle

      iii.    Not malleable

       iv. Not ductile

                     v.    Poor conductors of heat and electricity

       vi.   Low melting and boiling points

       vii.   Not sonorous

Examples of non-metals: carbon, sulphur, oxygen, hydrogen, iodine etc.

Exceptions in Physical Properties

                 Some elements show different physical properties. Such as

                          i.   Mercury is metal but exists as liquid at room temperature.

                      ii.     Gallium and caesium are metals have very low  melting points. They melt when placed on palm.

       iii.  Iodine is non-metal but show lustre.

       iv.   Graphite is non-metal but conduct electricity.

                        v.    Diamond is form of carbon but the hardest natural substance.

       vi.    Alkali metals like Li, Na and K are very soft metals 

Chemical Properties of Metals

Metals show characteristics reactions with oxygen, water, acid and salt solutions.

Reaction with oxygen: Metals react with oxygen to form metal oxides.

General reaction

Metal + Oxygen → Metal Oxide

Examples

2 Cu + O₂ →2CuO

4Al + 3O₂ →2Al₂O₃

Nature of Metal Oxides

Most metal oxides are basic in nature; they react with acids to form salt and water.

Example

CuO + 2HCl →CuCl₂ +H₂O

Amphoteric oxides

Some metal oxides show both acidic and basic properties. They are called amphoteric oxides.

Examples: Al and Zn

Al₂O₃ + 6HCl → 2AlCl₃ + 3H₂O

Al₂O₃ + 2NaOH → 2NaAlO₂ +H₂O

Formation of Alkali

Some metals oxides dissolve in water to form alkalis.

Examples

Na₂O + H₂O →2NaOH

K₂O + H₂O  →2KOH

Reaction of Metals with Water

Metals react with water to produce metal hydroxide and hydrogen gas.

General reaction

Metal + water →Metal oxide + Hydrogen

Metal oxide + water →Metal Hydroxide

Examples

2K +2H₂O → 2KOH +H₂ + heat

2Na +2H₂O → 2NaOH +H₂ + heat

Observations

                        i.    Potassium and sodium react very violently with cold water.

                      ii.    Calcium reacts less violently.

       iii.     Magnesium reacts with hot water.

       iv.   Aluminium, Zinc and iron react with steam.

                     v.      Lead, copper, silver and gold do not react with water.

Examples of Reaction of metals with steam

2Al + 2H₂O_(g) → Al₂O₃ +3H₂

3Fe + 2H₂O_(g) → Fe₃O₄ +3H₂

Reaction of Metals with Acids

Matals react with dilute acids to form salt and hydrogen gas.

General reaction

Mertal + dilute Acid →Salt + Hydrogen

Example

Mg+ 2HCl MgCl₂ + H₂

Reactivity order

Mg>Al>Zn>Fe

Copper does not react with dilute hydrochloric acid.

 

Special case – Nitric Acid

Nitric acid is a strong oxidising agent. It converts hydrogen into water, so hydrogen gas is not evolved.

Magnesium and manganese react with very dilute nitric acid to produce hydrogen.

Reaction of Metals with Salt Solutions

A more reactive metal displaces a less reactive metal from its compound (salt solution).

General reaction

Metal A + Salt of B →Salt of A + Metal B

Example

Fe + CuSO₄ → FeSO₄+Cu

Iron is more reactive than copper so it displaces copper from copper sulphate solution. This called displacement reaction.

Reactivity Series of Metals

The reactivity series is a list of metals arranged in order of decreasing reactivity.

Key points:

  

                      i.    Metals above hydrogen can displace hydrogen from acids.

                    ii.    Metals higher in the series displace metals lower in the series.

        iii.     Gold and silver are least reactive metals.

Formation of Ionic Compounds

Metals tend to lose electrons and form positive ions(cations) and non-metals gain electrons and form negative ions(anions).

Example

Na → Na⁺ + e^-

Cl + e^- → Cl^-

These oppositely charged ions attract each other by electrostatic forces forming ionic compounds.

Na⁺ +  Cl^- → NaCl

Properties of Ionic Compounds

Physical Nature

Ionic compounds are hard crystalline solids and brittle.

Melting and Boiling Points

Strong electrostatic forces between ions are strong so they require more energy to break. So ionic compounds have high melting and boiling points.

Solubility

Ionic compounds are soluble in water but insoluble in organic solvents like petrol, kerosene.

Conduction of Electricity

Ionic compounds do not conduct electricity in solid state but they conduct electricity in molten state or aqueous solution.

Occurrence of Metals

Metals are mainly obtained from the earth’s crust.

Mineral: Naturally occurring elements or compounds in the earth’s crust are called minerals.

Ore: Mineral that contain a large amount of metal and from which metal can be extracted economically are called ores.

Gangue: The impurities present in ores such as sand, soil and rock particles are called gangue.

Extraction of Metals

The process of obtaining metals from their ores is called metallurgy.

Metallurgy includes following main steps:

                      i.     Crushing of ores

                     ii.   Concentration of Ores (removal of gangue)

       iii.  Extraction of metal

       iv.   Refining of metal

Different methods are used depending on the reactivity of metals.

                     i.  High reactive metals are obtained by electrolysis. Examples: Na, K, Ca, Mg and Al

                   ii.   Moderately reactive metals are obtained by reducing with carbon after roasting or calcination. Examples: Zn, Fe, Pb.

        iii.     Low reactive metals are found in free state.  Examples :  Cu, Ag , Au .

Corrosion

Corrosion is the gradual destruction of metals due to reaction with air, moisture or chemicals.

Examples:

                        i.      Rusting of iron (formation of hydrated iron oxide)

                    ii.    Black coating on silver (formation of silver sulphide)

        iii.   Green coating on copper (Basic copper carbonate)

Rusting occurs when both air and water are present.

Prevention of Corrosion

Following methods are used to prevent corrosion:

                     i.          Painting

                  ii.      Oiling or greasing

      iii.    Galvanisation (coating iron with zinc)

      iv.     Chrome plating

                    v.      Anodising

      vi.      Alloying

Alloy

An alloy is a homogenous mixture of two or more metals or a metal and non-metal.

Examples

Brass : Copper + Zinc

Bronze : Copper + Tin

Stainless steel: Iron+ Chromium +Nickel

Solder: Lead+ Tin

Alloys have improved strength, hardness and corrosion resistance compared to pure metals.

These quick revision notes on Metals and Non-Metals of Class 10 NCERT Science.

Related Topics 

1. Chemical Reactions and Equations Quick Revision Notes

2. Acids , Bases and Salts Quick Revision Notes