Answer:
I suggest you See Explanation. But tldr: Carbon forms four bonds with no lone pairs.
Explanation:
By "rule of 8" I am assuming you mean "Octet Rule." In case you don't know, the octet rule (or rule of 8) is a rule referring to the maximum number of valence shell electrons that an atom can hold: 8 electrons. However, there are exceptions to this: octet-deficient and expanded octet atoms. Octet-deficient atoms follow what is known as the duet rule (or rule of 2), as seen in the case of H and He, or have have a capacity of up to 6 electrons in their valence shell, as seen in the case of B and Be. Expanded octets contain 10, 12, or even 14 electrons and occur in Period 3 elements and after. (It was previously assumed that this was due to d-orbital hybridization but that hypothesis has been disproven and currently an explanation regarding expanded octets doesn't exist. Yet another Nobel Prize worthy concept to solve when you have free time!)
Anyways, how does this all apply to Carbon being the backbone of the millions of organic molecules? Well, carbon follows the octect rule. Unlike duet rule atoms, it is not limited to one bond with another atom. Neither does it hold many lone pairs to itself nor form over four bonds at once causing a decrease in stability. No, Carbon forms four bonds with no lone pairs and has perfect stability in terms of both formal charge and octect rule in many of its structures. Its capacity to bond to up to 4 atoms without comprimising stability is the reason why carbon is the backbone of organic molecules. If you feel this answer helped, gimme brainliest, have a great day! :)