The valency of silicon is 4.
Silicon has an atomic number of 14, and its electronic configuration is 2, 8, 4. This means silicon has 4 electrons in its outermost shell (valence shell). To achieve a stable octet configuration (like the noble gases), silicon needs to either gain or lose four electrons.
Because it requires the transfer of four electrons, silicon's valency is 4. It can form four covalent bonds with other atoms. Silicon can exhibit both +4 and -4 oxidation states depending on the elements with which it interacts, but its fundamental valency related to its bonding capacity is 4.
