What are the two properties of carbon which lead to the huge number of carbon compounds we see around us?

Explanation

(i) Carbon has 4 electrons in its outermost shell and needs to pain or lose 4 electrons to attain noble gas configuration. Losing or gaining 4 electrons is not possible due to energy considerations, hence it shares electrons to form covalent bonds.
Two reasons for large number of carbon compounds are:
(ii) Catenation The unique ability of carbon to form bonds with other atoms of carbon giving rise to long chains of different types of conipounds.
(iii) Tetravalency : Since carbon has a valency of 4, it is capable of bonding with four other atoms of carbon or atoms of elements like oxygen, hydrogen, nitrogen, sulphur, chlorine, etc.
The reason for the formation of strong bonds by carbon is its small size which enables the nucleus to hold on to the shared pairs of electrons strongly.