Answer. Property of carbon atom which is responsible for formation of long chains of carbon atom compounds is catenation. It is ability of carbon atoms to link with other carbon atoms to form long chains and large rings. Carbon atom fulfils the two basic conditions to exhibit catenation.
(a) It has valence greater than two.
(b) It forms stronger bonds with its own atoms than that of its bonds with other atoms especially oxygen.
For example, both silicon and carbon have similar electronic configurations but carbon shows catenation whereas silicon does not. It is mainly due to the reason that C-C bonds are much stronger (355 kJ mol-1) than Si-Si (200 kJ mol-1) bonds. On the other hand, Si-O bonds are much stronger (452 kJ mo-1) than C-O bonds (351 kJ mol-1). Hence, silicon occurs in the form of silica and silicates in nature.