• Written By Sahana Soma Kodarkar

Chemical Properties of Metals: Overview, Properties, Examples

We know that metals are hard, ductile, malleable, good conductors of heat and electricity and have lustre. But some metals appear dull due to the formation of an oxide layer on their surface. Metals and non-metals exhibit several chemical properties. The chemical properties of metals differ from the chemical properties of non-metals.

The chemical reactivity of the metal determines the capacity of the reaction with oxygen. One of the chemical properties of metals is that it displaces hydrogen from water and dilute acids. In this article, we will provide detailed knowledge of the chemical properties of metals. Scroll down to learn more!

Metals and Non-metals

Metals are the elements (except hydrogen) that form positive ions by losing electrons (or donating electrons). Metals include iron, aluminium, copper, silver, gold, platinum, zinc, tin, lead, and mercury.

Non-metals are the elements that form negative ions by gaining electrons (or accepting electrons). Some of the examples of non-metals are Carbon, Sulphur, Phosphorus, Silicon, Hydrogen, Oxygen, Nitrogen, Chlorine, Bromine and Iodine.

Physical Properties of Metals and Non-Metals

The important physical properties of metals and non-metals are given below:

1. Physical State: Metals are generally solids at room temperature. Mercury and gallium are the only metals that exist in the liquid state at this temperature. Non-metals occur in all the three states-solids, liquids and gases at room temperature. For example, sulphur and phosphorus are solids; bromine is a liquid while oxygen, nitrogen, and chlorine are gases under ordinary temperature and pressure conditions.
2. Lustre: Metals have a shiny appearance. The characteristic shine of metals is called metallic lustre. Gold, silver, platinum, aluminium, iron, zinc, and tin are lustrous metals. In fact, because of this property, gold, silver and platinum are used to make jewellery and decorative items. When some metals are exposed to air, their lustre fades. This is because the metals react with the air and moisture in the atmosphere to form a thin oxide layer on their surface. When metals become tarnished, they are said to be tarnished metals. Non-metals have a dull appearance. Graphite, diamond and iodine are the only non-metals that have lustre.
3. Hardness: Most of the metals are hard and strong, except sodium and potassium, which are soft and these metals can be cut with a knife. The metals like iron, copper, tin are examples of some hard metals. Non-metals which are solids are not hard but they are soft and brittle except diamond which is solid but it is the hardest substance known.
4. Sonority: Metals are sonorous, which means they produce a ringing sound when struck, whereas non-metals are non-sonorous. Therefore, bells and strings of musical instruments are made of metals like iron, copper or alloys of metals.
5. Malleability: Metals can be beaten into thin sheets. This property is known as malleability. For example, an iron nail or wires made of copper, aluminium, silver, or gold will flatten into thin sheets when beaten with a hammer. Whereas non-metals are non-malleable.
6. Ductility: The property of the metal to be drawn into thin wire is known as ductility. Copper and aluminium wires are used for transmission of electricity while gold and silver are used for making jewellery. Metals are highly ductile in nature. Whereas non-metals are non ductile.
7. Conductivity:
a. Electrical conductivity: Metals are good conductors of electricity. Silver is the best conductor of electricity followed by copper and aluminium. Therefore, wires used to transmit electricity are made of copper and aluminium. Non-metals are either bad conductors or non-conductors of electricity. Wood, plastic, cotton, nylon are non conductors of electricity. Graphite, which is a good conductor of electricity, is an exception.
b. Thermal conductivity: Metals are good conductors of heat since they allow heat to pass through them easily. Therefore, utensils used for cooking food are made of metals. Non-metals like carbon, oxygen and nitrogen are bad conductors of heat.
8. Melting points and boiling points: Most of the metals have high melting points and boiling points. Sodium, potassium, and mercury are exceptions. Non-metals, except graphite and diamond, have low melting and boiling points.

Chemical Properties of Metals and Non-metals

Metals and non-metals show different chemical properties. First, we will discuss the chemical properties of metals. The most important chemical properties of metals are as follows:

1. Reaction of metals with oxygen (air)

When metals are burnt in air, they react with the oxygen of the air to form metal oxides. Metal oxides are basic in nature. Some of the metal oxides react with water and form alkalies.

$${\rm{Metal}} + \mathop {{\rm{Oxygen}}}\limits_{\left( {{\rm{Form}}\,\,{\rm{air}}} \right)} \, \to \,\mathop {{\rm{Metal}}\,{\rm{Oxide}}}\limits_{\left( {{\rm{Basic}}\,\,{\rm{oxide}}} \right)}$$

The chemical reactivity of the metal determines the capacity of the reaction with oxygen. Some metals react with oxygen even at room temperature, while others react only when heated, and still, others react only when strongly heated.

For example,
a. Sodium metal reacts with oxygen at room temperature and forms sodium oxide.

Sodium oxide is a basic oxide that reacts with water to form an alkali called sodium hydroxide.

Sodium and potassium metals are so reactive that they can react vigorously with oxygen, catch fire, and burn. Hence, potassium and sodium metals are stored in kerosene oil to prevent their reaction with oxygen and moisture.

b. Magnesium metal does not react with oxygen at room temperature. But on heating, magnesium metal burns in the air giving intense heat and light to form basic oxide called magnesium oxide. This indicates that magnesium is less reactive than potassium and sodium.

c. Aluminium metal burns in the air on heating to form a protective layer of aluminium oxide on its surface.

d. Zinc metal burns in the air only on strong heating to form zinc oxide.

e. Copper does not burn in the air, even on strong heating. However, on heating in the air for a long time, it gets covered with a layer of black coloured copper (II) oxide.

2. Reaction of Metals with Water

Metals react with water to form a metal hydroxide and hydrogen gas. All the metals, however, do not react with water. The intensity of the reaction of a metal with water depends on its chemical reactivity. Such as

a. Metals react with water to form a metal hydroxide and hydrogen gas. All the metals, however, do not react with water. The intensity of the reaction of a metal with water depends on its chemical reactivity. Such as

$${\rm{Metal + Water}} \to {\rm{Metal}}\,{\rm{hydroxide + Hydrogen}}$$

For example,

1. Potassium and sodium violently react with cold water and form potassium hydroxide and sodium hydroxide, respectively, with the release of hydrogen gas.

2. Calcium reacts with cold water and forms calcium hydroxide with the release of hydrogen gas.

3. Magnesium does not react with cold water. It reacts with hot water and forms magnesium hydroxide and hydrogen gas.

b. When a metal reacts with steam, metal oxide and hydrogen gas are produced.

$${\rm{Metal + Steam}} \to {\rm{Metal}}\,{\rm{oxide + Hydrogen}}$$

For example,
Metals like aluminium, zinc and iron do not react with either cold water or hot water. They react With steam to form a metal oxide and hydrogen.

1. Aluminium reacts with steam and forms aluminium oxide with the release of hydrogen gas.

2. Red-hot iron reacts with steam and produces iron (II, III) oxide with the release of hydrogen gas.

3. Zinc reacts with steam and produces zinc oxide with the liberation of hydrogen gas.

3. Reaction of Metals with Water

Metal usually displaces hydrogen from dilute acids. However, less reactive metals like copper and silver do not displace hydrogen from dilute acids. All metals that are more reactive than hydrogen, i.e. those which can lose electrons more easily than hydrogen, displace hydrogen from dilute acids to produce hydrogen gas. This is because the more reactive metals readily give electrons, and these electrons reduce the hydrogen ions of acids to hydrogen gas. When metal reacts with dilute acids, then metal salt and hydrogen gas are produced.

$${\rm{Metal}}\,{\rm{ + }}\,{\rm{Dilute}}\,{\rm{acid}} \to \,{\rm{Metal}}\,{\rm{salt}}\,{\rm{ + }}\,{\rm{Hydrogen}}$$

For example,

1. Sodium metal violently reacts with dilute hydrochloric acid and forms sodium chloride and hydrogen gas.

2. Aluminium metal at first reacts very slowly with dilute hydrochloric acid due to the presence of a thin protective layer. When aluminium coating becomes thin, it reacts with hydrochloric acid vigorously, forms aluminium chloride, and liberates hydrogen gas.

3. Iron slowly reacts with cold hydrochloric acid and forms iron (II) chloride with the liberation of hydrogen gas.

4. Copper does not react with hydrochloric acid. This shows that copper is less reactive than hydrogen.

When a metal reacts with dilute nitric acid, no hydrogen gas is produced. This is due to the fact that nitric acid is a strong oxidising agent. As a result, as soon as hydrogen gas is formed in the reaction between a metal and dilute nitric acid, the nitric acid oxidises it to water.

Very dilute nitric acid, however, reacts with magnesium and manganese metals to evolve hydrogen gas. This is because the very dilute nitric acid is a weak oxidising agent that cannot oxidise hydrogen to water. The reactions of magnesium and manganese metals with very dilute nitric acid are given below.

a. Magnesium reacts with very dilute nitric acid to form magnesium nitrate and hydrogen gas.

b. Manganese reacts with very dilute nitric acid to form manganese nitrate and hydrogen gas.

4. Reaction of Metals with Salt Solutions

When a more reactive metal is put in a salt solution of a less reactive metal, the more reactive metal displaces the less reactive metal from its salt solution. The more reactive metal takes the place of less reactive metal and forms its own salt solution.

For example,

1. When a more reactive metal is put in a salt solution of a less reactive metal, the more reactive metal displaces the less reactive metal from its salt solution. The more reactive metal takes the place of less reactive metal and forms its own salt solution.

5. Reaction of Metals with Chlorine

Ionic chlorides are formed when metals react with chlorine. Metal atoms lose electrons and become positively charged ions during the formation of metal chlorides, whereas chlorine atoms gain electrons and become negatively charged chloride ions.

For example,

1. Sodium metal readily reacts with chlorine and forms ionic chloride called sodium chloride.

2. Metals like magnesium, aluminium, iron, and copper react with chlorine on heating and form respective ionic chloride.

6. Reaction of Metals with Hydrogen

Most of the meals do not combine with hydrogen. Only a few metals such as sodium, potassium, calcium, and magnesium combine with hydrogen and form metals hydride.

For example,

1. Sodium hydride is formed when hydrogen gas is passed over heated sodium.

The most important chemical properties of non-metals are as follows:

1. Reaction Of Non-metals With Oxygen

Non-metal reacts with oxygen and forms acidic oxides or neutral oxides. Carbon forms an acidic oxide whereas hydrogen forms neutral oxides. The acidic oxides of non-metal dissolve in water and forms acid.

For example,

1. When carbon is burnt in a sufficient amount of oxygen, carbon dioxide is formed. The carbon dioxide forms carbonic acid when dissolved in water. The chemical reaction is as follows:

2. Reaction Of Non-metals With Water

Non-metals do not react with water or steam to evolve hydrogen gas. This is because non-metals cannot give electrons to reduce the hydrogen ions of water to hydrogen gas.

3. Reaction Of Non-metals With Dilute Acids

Non-metals do not react with dilute acids. Non-metals do not displace hydrogen from the dilute acids. For example, non-metals like carbon, Sulphur do not react with dilute hydrochloric acid or dilute sulphuric acid to produce hydrogen gas.

4. Reaction Of Non-metals With Salts Solution

A more reactive non-metal displaces less reactive non-metal from its salt solution.

For example, when chlorine gas is passed through sodium bromide, chlorine displaces bromine and forms sodium chloride and bromine.

5. Reaction Of Non-metals With Chlorine

Non-metals react with chlorine and form covalent chlorides which are generally non-electrolytes.

For example, when hydrogen reacts with chlorine, a covalent chloride is formed called hydrogen chloride.

6. Reaction Of Non-Metals With Hydrogen

Non-metal react with hydrogen to form covalent hydrides. Non-metal hydrides are formed by the sharing of electrons, that is, non-metal hydrides have covalent bonding.

For example,

Sulphur is a non-metal that combines with hydrogen to form a covalent hydride called hydrogen sulphide.

Differences Between Chemical Properties of Metals and Non-Metals

Below we have listed down the differences between the chemical properties of metals and non-metals. Let’s have a look at the differences:

Summary

Metals are hard, lustrous, malleable, ductile and good conductors, whereas non-metals are non-lustrous, non-ductile, non-malleable and bad conductors. Metals are more reactive than non-metals. Metals form basic oxides with oxygen, whereas non-metal form acidic oxides or neutral oxides with oxygen. The chemical reaction of metals depends on the reactivity of metals. Metal forms basic oxides, whereas, Non-metals form acidic oxides or neutral oxides.

FAQs on Chemical Properties of Metal

Q.1. What are the five chemical properties of metals?
Ans
: The five chemical properties of metals are-
a. Reactions of metals with oxygen
b. Reactions of metals with water
c. Reactions of metals with dilute acids
d. Reactions of metals with salt solution
e. Reactions of metals with chlorine

Q.2. What are the chemical properties of metal and non-metals?
Ans
: The chemical properties of metals are as follows:
Metals form a basic oxide, metal displaces hydrogen from water and dilute acids.
The chemical properties of non-metals are as follows:
Non-metals form acidic oxides or neutral oxides, non-metal do not react with water and hence do not displace hydrogen from water. Non-metals do not react with dilute acids and hence do not displace hydrogen from dilute acids.

Q.3. What are the physical and chemical properties of metal?
Ans
: Physical properties of metals: Metals are hard, ductile, malleable, lustrous and good conductors.
Chemical properties of Metals :
Metals form a basic oxide, Metals displace hydrogen from water, Metal displace hydrogen from dilute acids, Metal forms ionic chlorides with chlorine. These ionic chlorides are electrolytes but non-volatile and Metals usually do not combine with hydrogen. Only a few reactive metals combine with hydrogen to form ionic metal hydride.

Q.4. How many chemical properties do metals have?
Ans
: Metals have five chemical properties.

Q.5. What are chemical properties?
Ans
: A chemical property is a property or characteristic of a substance that is observed during a reaction that changes the chemical composition or identity of the substance.

Q.6. Is colour a chemical property?
Ans
: No, colour is a physical property.