Question

what causes the existance of very large number of carbon compounds

Answer 1

Carbon is the only element that can form so many different compounds because each carbon atom can form four chemical bonds to other atoms, and because the carbon atom isjust the right, small size to fitin comfortably as parts of verylarge molecules.

Having the atomic number6, every carbonatom has a total of six electrons. Two are in a completed inner orbit, while the other four are valance electrons—outer electrons that are available for forming bonds with other atoms.

The carbon atom's four valence electrons can be shared by other atoms that have electrons to share, thus forming covalent (shared-electron) bonds. They can even be shared by other carbon atoms, which in turn can share electrons with other carbon atoms and so on, forming long strings of carbon atoms, bonded to each other like links in a chain. Silicon (Si), another element in group 14 of theperiodic table, also has four valence electrons and can make largemolecules called silicones, but its atoms are too large to fit together into as great a variety of molecules as carbon atoms can.

Carbon's abilityto form long carbon-to-carbon chains is the first of five reasons that there can be so many different carbon compounds; a molecule that differs by even one atom is, of course, a molecule of a different compound. The second reason for carbon's astounding compound-forming ability is that carbon atoms can bind to each other not only in straight chains, but in complex branchings, like the branches of a tree. They can even join"head-to-tail" tomake rings of carbon atoms. There is practically no limit to the number or complexity of the branches or the number of rings that can be attached to them, and hence no limit to the number of different molecules thatcan be formed.