Metals and Nonmetals: Physical Properties, Chemical Behaviour and Uses (with diagram)

On the basis of their general properties, elements are often divided into two classes—metals and nonmetals. More than 110 elements are known today. Of these, 24 are nonmetals and the rest are metals.

Physical Properties:

We generally look for a metal when we need a strong material. This is because metals are in general hard and strong. Some examples of metals are potassium (K), calcium (Ca), sodium (Na), magnesium (Mg), aluminum (Al), iron (Fe), zinc (Zn), tin (Sn), copper (Cu), mercury (Hg), silver (Ag), gold (Au) and platinum (Pt).


Metals have the following general properties:

1. They are generally hard, strong solids, for example, aluminium, iron, zinc, tin and copper. They are strong enough to bear heavy loads, i.e., they have a high tensile strength.


Metals are lustrous and can be pressed into sheets or fails and drawn into wires


Sodium and potassium are soft solids which can be cut with a knife, and mercury is a liquid under ordinary conditions.

2. They have a lustre, known as metallic lustre. For example, aluminium, iron, zinc, copper, silver and gold are all lustrous. Such metals can be polished too.


Metals have a high tensile strenght

3. Metals are sonorous. When struck, they produce a sound called a metallic sound or metallic clink. Recall the ringing of a bell or the clink of coins.

4. Metals are malleable. In other words, they can be beaten or rolled into sheets. Aluminium, iron, copper or silver can be beaten or rolled into thin sheets. Common examples are the silver foil used to decorate sweets and aluminium foil used to pack foodstuff.

Metals are sonorous

5. Metals are ductile, i.e., they are flexible and can be drawn into wires. For example, iron, aluminium, copper, silver and gold can be easily drawn into wires.


Can you draw a wire from a piece of wood or coal? No, because wood and coal are brittle, not flexible.

6. Metals are good conductors of heat, i.e., they allow heat to pass through them easily. Due to this property, we use metal utensils in kitchens. Heat supplied at one place of the utensil is conducted all over it.

You cannot use a frying pan made of, say, cardboard because it is a bad conductor of heat. When placed over fire, cardboard does not distribute the heat all over the pan. Instead, it starts burning due to the localised heat.


7. Metals are good conductors of electricity, i.e., they allow an electric current to pass through them easily. This is why electricity is transmitted from one point to another through metal wires, like those of copper or aluminium.

Silver is the best conductor of electricity; the next best is copper and then aluminium. You cannot use nylon or jute ropes for electrical transmission, as nylon and jute are bad conductors of electricity.


In contrast to metals, nonmetals are not known for strength. They are

i. Usually lustreless (dull), except graphite and iodine,

ii. Brittle (if solid),

iii. Bad conductors of heat,

iv. Bad conductors of electricity (except graphite), and

v. Non-sonorous (i.e., they do not produce a metallic clink).

Of the 24 nonmetals known today,

vi. 12 are solids (e.g., carbon, silicon, phosphorus, sulphur, iodine),

vii. 1 is a liquid (bromine), and

viii. 11 are gases (e.g., hydrogen, nitrogen, oxygen, fluorine, chlorine, helium, neon, argon) under ordinary conditions.


Using an electrical circuit of the type shown in Figure 6.4, you can easily test whether or not something conducts electricity. The bulb will glow when the test material is metallic, like a key, but not when it is nonmetallic, like a block of wood.

Sharpen a small pencil at both ends, and connect the two naked ends of the ‘lead’ to the circuit. The bulb will glow, showing that the ‘lead’ of the pencil conducts electricity. The ‘lead’ of a pencil is made of a mixture of clay and graphite, and graphite (a form of carbon) is a good conductor of electricity.

Graphite conducts electricity

Chemical Behaviour of Metals:

Though most metals undergo similar kinds of reactions, the ‘vigour’ with which they react is not the same. Some are more active than others. Metals along with hydrogen (a nonmetal) are arranged in order of their activity in a series, called the activity series, shown in Figure 6.5. This series helps us understand the reactions of metals.

The activity series of some common metals

Action of air on metals:

The oxygen present in air acts on metals to form their oxides. Metals like potassium (K) and sodium (Na), placed high up in the series are so active that they react very fast with air, forming their oxides. So, potassium and sodium are stored under kerosene.

Magnesium, aluminium and iron react more slowly with air. When left exposed, they get tarnished (lose their sheen) because a thin film of oxide forms over their surface. On being heated in air (or oxygen), these metals react faster. For example, a piece of magnesium, when ignited, burns in air with a dazzling white light. When magnesium is burnt in an open gas jar, white solid particles of MgO are deposited on the inner wall of the jar.


The burning of magnesium in air

As you know, iron rusts slowly in moist air. Rust is a hydrated oxide of iron Fe203 xH20 (the number of H2O molecules varies).

Metals further down the series retain their sheen for a longer time because they do not react with air so easily. When strongly heated in air, copper forms a black oxide (CuO), but silver (Ag) and gold (Au) do not.

When the chemical action of the air is prolonged beyond tarnishing, the compounds formed slowly eat away the metal. This is called corrosion. Rusting (of iron) is a common example of corrosion. Other metals, like magnesium, aluminium, zinc and copper, also get corroded by the prolonged action of air. Copper forms a green solid on its surface, whereas the others (except iron) form greyish white solids.

Displacement of one metal by another:

A more active metal displaces a less active metal from compounds of the latter in solution. For example, aluminium and iron displace copper from a solution of copper sulphate.


Dissolve some crystals of copper (II) sulphate (CuSO45H2O, which is also called blue vitriol) in water. Place an iron nail in the solution. In a while, the portion of the nail which is inside the solution will become red. This is because a layer of copper gets deposited over the surface of the nail. The colour of the solution will slowly change from blue to green due to the formation of iron (II) sulphate.


You can repeat this activity using a piece of magnesium or aluminium instead of the nail. Copper will be deposited but the resulting solution will be colourless because magnesium sulphate and aluminium sulphate are colourless.

Iron displaces copper from a copper sulphate solution

Displacement of hydrogen from water:

Metals higher than hydrogen in the activity series displace hydrogen from water. Those below hydrogen do not. Also, the more active the metal, the more vigorously does it react with water. Thus potassium and sodium react vigorously even with cold water, while magnesium reacts only with steam. A burning piece of magnesium continues to burn vigorously, when brought in contact with steam.


Magnesium continues to burn in steam


You can perform the following activity with the help of your teacher. Cut a small piece of sodium and remove the kerosene by pressing the piece between the folds of a filter paper. Drop the piece of metal into a trough of water.

It melts to form a silvery white globule which darts about the surface of the water, with a hissing sound. You will also observe a yellow flame over the globule and hear intermittent ‘pops’. This is because the heat evolved in the reaction melts the metal and the hydrogen produced catches fire.

Sodium reacts vigorously with cold water

After the reaction, the ‘water’ of the trough will turn a red litmus paper blue because of the sodium hydroxide (an alkali) formed.

Displacement of hydrogen from acids:

Metals above hydrogen in the activity series displace hydrogen from dilute hydrochloric and sulphuric acids, but those below hydrogen do not. Also, the reactivity of the metal decreases down the series.

(a) Iron displaces hydrogen from dilute sulphuric acid, (b) Magnesium reacts more vigorously with an acid than iron does


Will copper or silver liberate hydrogen from dilute acids? No, because they are less active than hydrogen.

Reactions with bases:

Only some metals (e.g., aluminium and zinc) dissolve in alkalis like sodium hydroxide and potassium hydroxide, forming salts and liberating hydrogen. Remember that these reactions do not occur with ammonium hydroxide, which is also an alkali.

Aluminium + potassium hydroxide → potassium aluminate + hydrogen

Zinc + sodium hydroxide → sodium zincate + hydrogen

Chemical Behaviour of Nonmetals:

Nonmetals are more reactive with metals than with other nonmetals. For example, chlorine acts on sodium forming sodium chloride, and oxygen acts on sodium forming sodium oxide, but chlorine does not react with oxygen. Generally, nonmetals react with each other only at high temperatures.

Action of air:

Except white phosphorus (phosphorus has many varieties—white, red, black), nonmetals do not react with air at room temperature. White phosphorus burns in air (or oxygen) at ordinary temperatures to form its oxides. Hence, it is stored under water.

Hydrogen, when lighted in air (or oxygen), burns with a ‘pop’ to form water.


When ignited in air (or oxygen), carbon and sulphur burn to form carbon dioxide (CO2) and sulphur dioxide (SO2) respectively. In an insufficient supply of air, carbon also forms carbon monoxide (CO).


Action of water:

In general, nonmetals do not react with water. However, chlorine dissolves in water to form an acidic solution. When the solution is placed in sunlight or heated, oxygen is liberated and hydrochloric acid is left behind.


When steam is passed over red-hot coke (carbon), a gaseous mixture of carbon monoxide and hydrogen is formed. This mixture, called water gas, has a great many industrial uses.


Displacement of one nonmetal by another from a salt solution:

Like metals, nonmetals also differ in their re-activities. This is better observed among elements with similar properties, which are said to form a family. For example, fluorine (F), chlorine (CI), bromine (Br) and iodine (I) constitute the halogen family.

Among the common halogens (CI, Br and I), chlorine is the most active, bromine less so than chlorine, and iodine the least. So chlorine displaces bromine and iodine from the solutions of sodium bromide and sodium iodide.


Generally, acids and bases do not act on nonmetals under ordinary conditions.

Uses of Metals:

From safety pins to bridges, metals are used to make a multitude of things which are an integral part of our lives.

1. Copper wires are generally used for domestic wiring and aluminium wires for long-distance electrical transmission. Aluminium is lighter and cheaper than copper.

2. Iron is a very useful metal as it is tough, strong and cheap. It is used for making tools, machines and agricultural equipment, and also in house construction.

To prevent rusting, iron is often galvanised. In this process, an iron article is immersed in molten zinc and then allowed to cool. Zinc forms a firm coating over iron and prevents rusting. Galvanised iron is used to make trunks, water pipes, barbed wire and wire nets. Iron coated with tin is used to make cans.

3. Iron, aluminium and copper are used in making utensils.

Magnesium is used in fireworks

4. As you know, magnesium burns in air with a dazzling white light when ignited. Therefore, it is used in fireworks.

5. Mercury does not stick to glass. At the same time, it is a good conductor of heat. So it is used for making thermometers.

6. Silver, gold and platinum are called noble metals as they do not easily react with other substances. Once polished, they retain their sheen for a long time. They are, therefore, used for making jewellery. Gold is mixed with small amounts of silver and copper to make it tough.

7. Alloys are homogeneous solid mixtures of metals, or of metals and nonmetals. Alloying is done to make the parent metal stronger. Some common examples of alloys are steel (a mixture of iron, very small amounts of carbon and manganese), brass (a mixture of copper and zinc) and bronze (a mixture of copper and tin).

8. Aluminium foil, which is very light, is used to pack food, medicines, etc. Aluminium is also used for making electric wires and utensils.

9. Artificial teeth were earlier usually made of silver or gold. Tooth cavities are filled with what are known as dental amalgams—alloys of silver or Fig. 6.12 Uses of aluminium tin with mercury.

Uses of aluminium

Uses of Nonmetals:

Let us study the uses of some common nonmetals.


Oxygen is perhaps the most important nonmetal in our lives. We and most other living beings need it for respiration.

Some of its other uses are as follows:

i. All combustion processes need oxygen.

ii. With acetylene, oxygen is used in oxyacetylene torches to cut and weld metals.

iii. It is required for the extraction of metals from their ores and for the production of steel from iron.

iv. It is used in the manufacture of sulphuric and nitric acids.

v. Liquid oxygen is used to burn rocket fuel.


i. Plants use nitrogen to manufacture proteins.

ii. Liquid nitrogen is used to preserve blood, corneas or other donated organs.

iii. Due to its inertness (non-reactivity), it is used for filling food packages. (Food does not go bad in an inert medium.)

iv. It is used in the manufacture of ammonia and urea.


Charcoal and lampblack are non-crystalline forms of carbon. Carbon is found in two crystalline forms—diamond and graphite, which have the following uses.

Uses of carbon in pencils, in jewellery, in cells (as electrodes) and in glass cutters

i. Diamond is used as a gem as also for cutting rocks or glass.

ii. Graphite is a good conductor of electricity and is, therefore, used as an electrode.

iii. Graphite is a good lubricant. Since its melting point is high, it can be used as a lubricant in machines that acquire high temperatures while being operated.

iv. Graphite is also used in the manufacture of pencils.


This yellow solid has several uses.

i. It is used in the manufacture of dyes, matches, fireworks and gunpowder.

ii. It is used in many medicines and as a fungicide to kill harmful fungi.

iii. It is also used to treat rubber and to manufacture sulphuric acid.


This greenish yellow gas has the following uses.

i. It is used in the manufacture of the useful plastic, polyvinyl chloride (PVC).

ii. It is used to disinfect water, as it kills germs. This is done either by passing chlorine gas through water or by treating water with bleaching powder.

iii. It is used as a bleaching agent in the paper and textile industries. Household bleaching agents also contain chlorine compounds.

iv. Chlorine is used in the manufacture of hydrochloric acid.

v. It is also used in the manufacture of pesticides, like Gammexane.


Though a nonmetal, iodine is a lustrous black solid. It sublimes slowly to form a violet vapour over the solid inside a stoppered bottle.

Uses of iodine

i. Iodine is an antiseptic. A solution of iodine in alcohol (with some potassium iodide) is known as tincture of iodine. Tincture of iodine is reddish brown, and is applied on cuts. A paste of iodine in petroleum jelly gives relief from pain.

ii. In the form of a compound, it is used in iodized salt to prevent diseases like goitre.

Noble gases:

Helium, neon, argon, etc., are called noble gases because of their nonreactive nature.

i. Helium is used to fill balloons. A mixture of helium and oxygen is used by divers for respiration.

ii. Neon is used for illumination. It glows an orange-red in advertisement signs.

iii. Argon is used to fill electric bulbs. When mixed with a little mercury vapour, it glows green in advertisement signs.

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