Silicon is element number 14, with the symbol Si. Silicon dioxide, silicon joined with oxygen, is a main material of the rocks at the Earth’s surface. Silicon is also the semiconductor used in computer chips.
Atomic number 1428.09
SiSiliconケイ素 (keiso)
Symbol
Si
Atomic weight
28.09
Place in the table
Period 3 · Group 14
Atomic weight from the Chemical Society of Japan, “Table of Standard Atomic Weights with Four Significant Figures (2026)”.
The star of rocks and sand
Silica (silicon dioxide) and minerals containing silicon are the main materials of the Earth’s crust. People once used the rock itself for building, and today they turn it into glass and ceramics used in advanced machines.
The symbol Si comes from the Latin silicium, which comes from the Latin word for flint, a stone made of silicon dioxide.
Silicon for semiconductors
Silicon itself is a semiconductor. Semiconductor circuits are made from silicon crystals.
The raw material is silica stone. When it is mixed with carbon and heated strongly, the oxygen leaves as carbon dioxide and carbon monoxide, and silicon about 99% pure is left.
Think about it
Q1The sand and stones in a park may contain silicon. How could you find out?
Q2Computer chips start from ordinary stone. What do you think about that?
Q3Where is glass used around you?
There is no single right answer. Talking it over with someone at home is a good way to learn.
Did you know? — The English name “silicon” was made to match the ending of “carbon,” its neighbor directly above it in Group 14.