What is metal?
A metal in chemistry is defined as an element that can easily form positive ions called cations and tends to make metallic bonds. The metals are distinguished by their chemical and physical properties such as malleability, ductility, ionization and bonding properties etc.
Properties of Metals
Examples of metals are gold, aluminium, iron and magnesium etc. They show the following properties
Physical Properties of Metals: Some of the main physical properties of metals are given below.
Metals can be hammered into thin sheets. It means they possess the property of malleability.
Metals are ductile. They can be drawn into wires.
Metals are a good conductor of heat and electricity.
Metals are lustrous which means they have a shiny appearance.
Metals have high tensile strength. It means they can hold heavyweights.
Metals are sonorous. It means when we strike them, they make a ringing sound.
Metals are hard. It means they cannot be cut easily.
Chemical Properties of Metals: Some of the chemical properties of metals are given below.
Reaction with Oxygen – Metals react with oxygen and form metallic oxides which are basic in nature.
Metal + Oxygen Metal oxide
Metal oxide + water Base
Example –Magnesium is metal and when it reacts with oxygen, it forms magnesium oxide. When we dissolve magnesium oxide in water, it gives magnesium hydroxide. The reactions are given below.
2Mg + O2 2MgO
MgO + H2O Mg(OH)2
An aqueous solution of metal oxide turns red litmus paper into blue.
Reaction with water – Metals react with water. When a metal reacts with water, metal hydroxide and hydrogen gas are formed.
Metal + Water Metal hydroxide + hydrogen
Example – Sodium metal reacts with water and forms sodium hydroxide and hydrogen gas. The reaction is given below –
Na + H2O NaOH + H2
Reaction With Acid – Metals react with acids and form salt and hydrogen gas. Some metals vigorously react with acids.
Metal + Acid Metal salt + hydrogen
Example – Magnesium metal reacts with hydrochloric acid and forms magnesium chloride and hydrogen. The reaction is given below –
Mg + 2HCl MgCl2 + H2
Reaction With Base – Metals react with bases such as sodium hydroxide and form salt and hydrogen gas.
Metal + Base Metal salt + hydrogen
Example – Aluminium metal reacts with Sodium hydroxide and forms sodium aluminate and hydrogen gas. The reaction is given below –
Al + NaOH NaAlO2 + H2
Displacement Reaction – A more reactive metal displaces a less reactive metal from its salt solution. These types of reactions are called displacement reactions.
Example – Iron is more reactive than copper. So, it displaces copper from its salt. The reaction is given below –
CuSO4 + Fe FeSO4 + Cu
What is non-metal?
A non-metal in chemistry can be defined as a chemical element that generally in a chemical reaction gains electrons when reacts with a metal. It has a tendency to form an acid if combined with oxygen and hydrogen. More variety in colour and states are displayed by the non-metals in comparison to metals.
Properties of Non-metals
Examples of non-metals are chlorine, carbon, bromine, sulphur, phosphorus etc. They show the following properties :
Physical Properties of Non-metals: Some of the major physical properties of non-metals are given below.
Non-metals cannot be hammered into thin sheets. It means they don’t possess the property of malleability. Instead, they are brittle as they break down into pieces on hammering.
Non-metals are not ductile. They cannot be drawn into wires.
Non-metals are poor conductors of heat and electricity.
Non-metals are not lustrous which means they are not shiny. Instead of dull in appearance.
Non-metals have low tensile strength. It means they cannot hold heavyweights.
Non-metals are not sonorous. It means when we strike them, they do not make any sound.
Non-metals are soft. It means they can be cut by knife easily.
Chemical Properties of Nonmetals: Some of the chemical properties of elements are given below.
Reaction with Oxygen – Nonmetals react with oxygen and form nonmetallic oxides which are acidic in nature.
Nonmetal + Oxygen Nonmetal oxide
Nonmetal oxide + water Acid
Example – Sulfur is a nonmetal and when it reacts with oxygen, it forms sulfur dioxide. When we dissolve sulfur dioxide in water, it gives sulfurous acid. Reactions are given below.
S + O2 SO2
SO2 + H2O H2SO3
The aqueous solution of nonmetal oxide turns blue litmus paper into red.
Nonmetals generally do not react with water.
Nonmetals do not react with dilute acids although they can react with concentrated acids.
Example – C + conc. 4HNO3 CO2 + 4NO2 + 2H2O
Nonmetals react with strong bases but do not produce hydrogen gas. These reactions generally take place at high temperatures.
Example – 4S + 8NaOH Na2SO4 + 3Na2S + 4H2O (At >600 ℃)
A more reactive nonmetal displaces a less reactive nonmetal from its salt solution.
Example – Bromine is more reactive than iodine. So, it displaces iodine in potassium iodide compounds. The reaction is given below –
2KI + Br2 2KBr + I2
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