Silicon

Silicon is a chemical element. It finds considerable applications as its a natural semiconductor and can be doped to produce more useful semiconductors with electrical conductivity that we can control. Silicon has an electronic configuration of:

$$1s^{2}2s^{2}2p^{6}3s^{2}3p^2$$

i.e., there are 4 valence electrons in $3s$ and $3p$. It has a diamond cubic crystal structure.