Question

If silicon also has four elements in outer shell then why we study carbon only?

Answer 1

because of carbon has small size and show inert pair effect and in silicon it has vacant d orbitals and due to poor shielding of d electrons it not participate more than carbon

Answer 2

Silicon is more of a stable element compared to carbon. It cannot be reacted to other elements or compounds as easily as carbon. Silicon is more of a solid element(metal). Carbon is more reactive.