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

The two properties of carbon which lead to the huge number of carbon compounds we see around us are Catenation and Tetravalency.

Catenation can be defined as the covalent bonding of the carbon atom to form chains. It can be classified into different types such as Straight chain, Branched-chain, and Cyclic ring according to that it can be modified.

In tetravalency, as the name indicate that tetra means four. Four electrons are present in the outer shell of the Carbon atom. Therefore, it has the 'ability to bond' with another four atoms.