In it's three stable configurations, silicon is made up of 14 protons, 14 to 16 neutrons, and 14 electrons. There are 20 other isotopes of silicon that feature anywhere from 8 to 30 neutrons. However, all but two of these decay in a matter of seconds or milliseconds.
Silicon is the second most abundant element on Earth and is found most often in the crust bonded with two oxygen atoms to form silicon dioxide. This compound presents most often as common sand, but can take on other mineral forms. Silicon also joins with carbon to create silicon carbide, used as a diamond-hard abrasive.