Materials: Metals and Non-Metals

Introduction

Metals and non-metals combine with each other to form different types of bonds. While metal combines with non-metal to form an ionic bond, non-metal combines with another non-metal to form covalent bond. Metals are said to have low ionisation energy and low electron affinities. Metals tend to lose electrons easily due to low electron affinity. On the other hand, non-metals have high ionisation energy and high electron affinities and hence tend to gain electrons easily. 

Physical Properties of Metals and Non-metals:

•   Appearance: Metals are lustrous meaning they are shiny in appearance whereas non-metals do not.
•     Malleability: This property of metals states that metal can be beaten into thin sheets. Generally, Metals are malleable while Non-metals are non-malleable.
•   Conductor of Heat and electricity: Metals are good conductors of heat and electricity whereas non-metals are poor conductors.
•   Ductility: This property of metal states that metal can be drawn into wires. Generally, Metals are ductile while Non-metals are not.
•   Sonority: Metals produce a ringing-like sound when struck hard, ringing sound produced is called to be sonorous whereas non-metals are non-sonorous. 

Some exceptions are sodium and potassium as they are soft metals and can be cut with a knife. Mercury on the other hand is also considered as an exceptional metal as it is found in a liquid state at room temperature.

Chemical Properties of Metals and Non-metals:

•   Reaction with Oxygen: Metal oxides are produced in the reaction between oxygen and metal which are basic in nature. Non- metallic oxides are produced when non-metals react with oxygen and are acidic in nature.
•   Reaction with Water: Metals on reaction with water produce metal hydroxides and hydrogen gas. Non-metals do not react with water and hence non-metals are reactive in air and are stored in water. For example, Phosphorus.
•   Reactions with Acids: Metals on reaction with acids produce metal salts and hydrogen gas. Non-metals do not react with acids.
•     Reactions with Bases: Metals on reaction with bases produce hydrogen gas. Reactions of non-metals with bases follow a complex process.

One of the reactions that occurs in metals is Displacement Reactions. In this reaction less reactive metals are displaced by more reactive metals from their compounds in aqueous solutions. For example, Zinc can displace Copper and Iron.

Atoms and Elements:

•  When a substance cannot be broken down further by chemical reactions, cooling, heating, or electrolysis, it is called an ‘element’. For example, Sulphur, Iron, and Carbon.
•  Atom is the smallest unit of an element. Any element contains only one kind of atom.
•  The atom remains unaffected by physical changes in the element. For example, an atom of liquid sulphur  would be the same as the atom of solid or vapour sulphur.
•  There are not more than 94 naturally occurring elements.
• Most of the elements are metals and the rest constitute either non-metals or metalloids. Metalloids possess the characteristics of both metals and non-metals.

Uses of Metals and Non-metals:

Metals are used in machinery, automobiles, aeroplanes, trains, satellites, industrial gadgets, cooking utensils, water boilers, etc. 

Followings are some of the uses of non-metals:

• Oxygen- Essential for our life.
• Nitrogen- used in fertilisers to enhance the growth of plants.
• Chlorine- used in the water purification process.
• Iodine- used as an antiseptic.
•  Phosphorus- used in crackers.

Conclusion:

Metals and non-metals can be differentiated easily by knowing their physical properties like boiling point, melting point, ductility, malleability, thermal conductivity and chemical properties like electronegativities. Oxidising and reducing properties, corrosion properties, etc. The distinct feature that helps in differentiating metals and non-metals is metals like aluminium and copper is a high thermal and electrical conductivity, whereas non-metals like sulphur and phosphorus metal are the insulators. Some examples of metals include copper, silver, gold, caesium, platinum, aluminium, iron, nickel etc. Examples of non-metals are oxygen, nitrogen, potassium, sulphur, arsenic, selenium etc.