Question

Carbon has atendencyto form long chain compounds but silicon does not why

Answer 1

because silicon is the metalloid

Answer 2

carbon has catenation tendency that is why it can form long chains
whereas silicon chains do exist but only about 3-4 silicon atoms...it is becoz atomic radius of silicon is greater than carbon..therefore carbon has more nuclear charge and can therefore more force to hold the atoms together...
silicon has less catenation force nd hence weak bonds are formed nd to only some extent