Silicon (Z=14): The Key Element of Earth and Modern Technologies

Essential Role of Silicon

Silicon (symbol Si, atomic number 14) is a chemical element abundant in the Earth's crust and a major constituent of minerals such as silicates. It plays a fundamental role in many modern technologies, particularly in the semiconductor industry.

Contribution of Silicon in Technologies

Silicon is at the heart of modern electronics, especially due to its semiconducting properties that enable the manufacture of components such as computer chips and transistors.

History of Discovery

1824: First isolation by Jöns Jacob Berzelius
Silicon was first isolated by the Swedish chemist Jöns Jacob Berzelius in 1824. He was the first to recognize the importance of silicon in silicates and its unique molecular structure.

1854: Link with semiconductors
In the 20th century, the semiconducting properties of silicon were highlighted, leading to its use in modern electronic circuits.

Atomic Structure

Constitution: The silicon atom has 14 protons, 14 neutrons, and 14 electrons, with an electronic configuration of 1s² 2s² 2p⁶ 3s² 3p².
Isotopes:

• Silicon-28 (²⁸Si): stable isotope, representing 92.23% of natural silicon.
• Silicon-29 (²⁹Si): stable isotope, used in crystallography research.
• Silicon-30 (³⁰Si): stable isotope, used in the study of geochemical processes.

Physical Properties

• Crystalline solid at room temperature.
• Molar mass: 28.085 g/mol
• Melting point: 1687 K (1414 °C)
• Boiling point: 3538 K (3265 °C)
• Density: ~2.3296 g/cm³ (at 20°C)
• Soluble in strong acids but resistant to water and many other solvents.

Chemical Reactivity

• React with oxygen to form silicon oxides, such as silicon dioxide (SiO₂), a major constituent of sand and rocks.
• Forms compounds with halogens and metals to create silicates and alloys.
• Does not easily react at room temperature with acids or bases, giving it remarkable stability.

Industrial and Technological Applications

• Manufacture of semiconductors for the electronics industry, including transistors and computer chips.
• Used in the production of solar panels due to its semiconducting properties.
• Employed in the manufacture of glass, ceramics, and refractory materials.
• Used in metal alloys to improve heat resistance and durability.

Biological and Ecological Role

• Silicon is an essential trace element in plant growth, particularly in the formation of plant cell walls.
• It plays an important role in bone formation in some animals, although its exact role is still under study.
• Diatoms, a group of microscopic algae, use silicon to form shells made of silicon dioxide, a fundamental aspect of the marine ecosystem.

Environmental and Industrial Challenges

• Although relatively abundant, silicon is intensively used in the technology industry, creating a growing demand for its extraction and processing.
• Silicon waste from the manufacture of solar panels and electronic devices poses environmental challenges related to their recycling and management.