METALS AND NON-METALS
Occurrence of non metals
1.Occurrence of hydrogen
In free state, it is found in the mixed form with coal gas .Free hydrogen is
found in the sun and the stars.
In combined form ,hydrogen is found
1. in natural gas and petroleum.
2. in water.
2.Occurrence of nitrogen
In free state, it is found in the air. 78% of air is composed of nitrogen.
In combined state, nitrogen is found
1. as a constituent of animals and plant proteins.
2. as chile saltpeter(NaNo3) and (KNO3) nitre.
3.Occurrence of oxygen
It occurs in free state in the atmosphere forming about 23% by mass of the
atmosphere.
1.In combined state it constitute about 89% by mass of water
2.It is also present in the combined state in the earth crust as
oxides,carbonates and silicates of metals.
4.Occurrence of silicon
Silicon does not occur free in nature.
In the combined state it occurs as silica and silicates .The most common
form of silica is sand.
5.Occurrence of carbon
In free state it is found as graphite,diamond and coal.
In the combined state
1.air consists of 0.03% carbon di oxide
2.in the earth crust it occurs as carbonates of the metals and as fossile fuels.
3 it is the central element of all the living matter.
6. Occurrence of sulphur.
In free state sulpur occurs in the earth crust.
In the combined state.
1.it occurs in rocks as metals sulphates and sulphides.
2.it is also present as Hydrogen sulphide which is present in petroleum and
natural gas.
Noble gases such as helium ,neon, argon, krypton and xenon occurs in
elemental form in air
Occurrence of metals
In nature most metals occur in combined state as minerals.
A mineral from which a metal can be extracted convenientely and profitably
is called an ore.
The minerals , present as impurities are called gangue.
Ores of common metals.
Name of the ore
Rock salt
Dolomite
Bauxite
Pyrite
Hematite
Copper glance,
Zinc blende
Chemical
formula
NaCl
CaCo3.MgCO3
Al203
Fes2
Fe2O3
Cus
Zns
metal
Kind of ore
Na
Ca
Al
Fe
Fe
Cu
Zn
Halides
Carbonates
oxide
sulphide
Oxide
Sulphide
sulphide