Question

How many single covalent bonds must a silicon atom have?

Answer 1

Hint: Silicon $(Si)$ is a metalloid which is placed in Group-14 of the periodic table. Its atomic number is $14$ and electronic configuration of $\left[ {Ne} \right]3{s^2}3{p^2}$ as the nearest noble gas is Neon ($Ne$).

Complete step by step answer:
Silicon $(Si)$ is tetravalent in nature just like Carbon ($C$) . That means it can easily share all four of its valence electrons to form covalent bonds with other atoms or molecules. So in order to be stable, Silicon$(Si)$needs to form four covalent bonds. Like Carbon ($C$), it can form covalent bonds with Hydrocarbons. The simplest silane that we can think of here is $Si{H_4}$.
In $Si{H_4}$, we can clearly see that one atom of $Si$ forms covalent bonds with four atoms of Hydrogen ($H$). Thus the Silicon atom gets its octet complete along with Hydrogen who completes its duet. Similar example can also be seen in case of$Si{(C{H_3})_4}$, where we can see four single covalent bonds being formed with the Methyl $(C{H_3})$ group.
Thus it is evident that the silicon atom must have $4$ single covalent bonds in order to complete its octet and be stable.

Additional Information- Silicon$(Si)$ has an energy band gap of $1.12eV$ at $0K$. $Si$ can readily react with oxygen and easily form oxides. The compound Silicon Dioxide$(Si{O_2})$ is widely used as an insulator in IC chips due to its proper stable chemical nature, unlike Gallium$(Ga)$which is soluble in water and easily decomposes at around $800$ degree Celsius.

Note:
When Silicon is crystallized, it gives up to $8$ electrons to bond around each nucleus of the atom. This allows Silicon$(Si)$ to be doped with other impurities to allow the semiconductor to be an n-type or p-type semiconductor accordingly and also increasing the conductivity of the material.