Saturday, 17 January 2015

5.1 Formation of Compounds

Stability of noble gases
■ Elements

Can combine to form compounds.

Noble gases, sulphur, gold, silver and diamond exist in their free states.

Other elements exist as compounds.
■ Compound

A compound is a substance formed when two or more chemical elements are chemically bonded together in fixed ratios.

Most minerals (compound) on the earth's crust are metallic oxides and sulphides.

The tendency of elements to combine with other elements show that compounds are more stable than their constituent elements.
■ Stability of noble gases

All noble gases are very stable, inert and inactive chemically.

The noble gases do not donate, receive or share any more electrons, as their valence shells are full.
■ Formation of chemical bonds

All other elements combine chemically with other elements to attain the stability of the noble gases.

Two types of chemical bonds in compounds are :
Ionic bonds : Donating / receiving electrons to form ionic compounds.
Covalent bonds : Sharing electrons to form covalent compounds
■ This video contains information on the formation of compounds.

⇲ For exercise(objective and subjective), download for free on Android OS.

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