element occurrence

Occurrence of Elements in Nature - A large number of elements occur inside or around the earth. Less reactive elements, like platinum, gold, nitrogen, oxygen etc., occur in free (native) state. Chemically active elements always occur in the combined..

A large number of elements occur inside or around the earth. Less reactive elements, like platinum, gold, nitrogen, oxygen etc., occur in free (native) state. Chemically active elements always occur in the combined state i.e. in the form of compounds containing t..

Occurrence - Noble gases always occur in free state because of their inert nature. All the noble gases, except radon are present in air in small amounts. The relative abundance of the noble gases in air is = 1%. Helium is present in natural gas up to the extent of 10 per cent. It is also ..

Chlorine belongs to the 'halogen' family. All the elements of this family are non-metals. They exhibit similar properties and they all form salts similar to sodium chlorid..

Astatine the last member of halogen family is a radioactive element with a very short life. All other halogens are abundant in nature in the combined state. The very high electronegativities of halogens make them very reactive and hence, they are not found in free stat..

Noble gases always occur in free state because of their inert nature. All the noble gases, except radon are present in air in small amounts. The relative abundance of the noble gases in air is = 1%. Helium is present in natural gas up to the extent of 10 per cent. It is also present in small ..

Astatine the last member of halogen family is a radioactive element with a very short life. All other halogens are abundant in nature in the combined state. The very high electronegativities of halogens make them very reactive and hence, they are not found in free state. In the combined s..

Alkali and alkaline Earth metals are the most violently active of all the metals. These occur in the combined form with halide, sulphate, carbonate, silicate ions, etc. and are not found in the free state in nature, as these are readily oxidized. A number of alkali and alkaline Earth metals are fo..

Occurrence and Extraction - Sulphur occurs in the earth's crust to the extent of 0.05% mostly as metal sulphides and sulphates. It also occurs in the elemental form in large underground beds. Another major source of sulphur is H 2 S present in the natural gas and crude oil. Sulp..

Aluminium is the third most abundant element (8.3% by weight) in the earth's crust after oxygen (45.5%) and silicon (25.7%..