Silicon, a tetravalent metalloid with atomic number 14, is the eighth most common element in the universe and is primarily used in semiconductors, solar cells, and alloys. While generally non-toxic, exposure to silicon dust can cause silicosis, a serious lung disease, particularly highlighted by the Hawk's Nest Tunnel disaster where many workers were affected. Silicon is essential for human health and plays a significant role in agriculture but can have environmental impacts when produced or disposed of improperly.

1. SILICON

2. INTRODUCTION
• Silicon belongs Group IV-A and 3rd
Period with atomic number 14.
• It is a tetravalent metalloid.
• It is the eighth most common element in the universe by mass, but
very rarely occurs as the pure element in the Earth's crust.
• Silicon was first isolated and identified as an element by Jöns Jacob
Berzelius, a Swedish chemist, in 1824.

3. PROPERTIES
• Silicon is a shiny, grey, metallic-looking solid with a high
melting point of 1414°C (2577°F) and a boiling point of
3265°C (5909°F).
• It is a hard, brittle solid with a diamond cubic crystal
structure.
• Chemically, silicon is relatively inert at room temperature
but can react with strong oxidizing agents and acids. It
readily oxidizes to form silicon dioxide (SiO2), a stable,
protective layer.
• Silicon is insoluble in water and most organic solvents.
• It is not flammable but can react with some substances at
high temperatures.

4. NATURAL OCCURANCE
Quartz
Sand
Meteorites
Rocks and
Minerals
Plant and
animal tissue

5. SILICA CYCLE

6. USES
• Semiconductors: Silicon is the most widely used semiconductor material in electronic
devices, including diodes, transistors, and integrated circuits.
• Solar Cells: Silicon is a key component in the production of solar cells, where it converts
sunlight into electricity in photovoltaic panels.
• Silicones: Silicones are synthetic polymers derived from silicon, used in sealants,
adhesives, lubricants, medical applications, and cosmetics .
• Alloys: Silicon is used as an alloying element in the production of aluminum alloys,
ferrosilicon and other metals to improve their properties.
• Glass and Ceramics: Silicon is used in the production of glass and ceramics, where it
enhances the strength and heat resistance of the materials.
• Energy Storage: Silicon is being researched for its potential use in next-generation lithium-
ion batteries due to its high theoretical capacity and abundance.

7. EFFECTS
• Health Effects: Silicon is generally non-toxic and essential for human health,
playing a role in the formation of connective tissues, bones, and nails. However,
exposure to silicon dust or fumes in industrial settings can cause respiratory
issues such as silicosis, a lung disease. It can also cause skin and eye infections.
• Environmental Effects: Silicon itself is not considered harmful to the
environment. However, the production and disposal of silicon-based products,
such as silicones, have environmental impacts if not managed properly.
• Biological Effects: Silicon is an essential element for many plants, and it is used
as a supplement in agriculture to improve plant growth and health. However,
excessive levels of silicon in water are harmful to some aquatic organisms.

8. HAWK’S NEST TUNNEL DISASTER
• The Hawks Nest Tunnel disaster occurred in the 1930s during the
construction of a hydroelectric tunnel in West Virginia, to divert water from
the New River to a hydroelectric power plant.
• The area was rich in silica rocks. When these rocks were drilled and crushed
during the construction process, they released silica dust into the air.
Workers were exposed to high levels of silica dust while digging the tunnel.
• The dust caused a lung disease known as silicosis, which is incurable and
often fatal. The working conditions were extremely poor, with inadequate
ventilation and safety measures in place. As a result, hundreds of workers
died from silicosis.

9. TOXICITY
• Silicon, in its elemental form, is not considered toxic. It is a naturally
occurring element and is found in many foods and beverages. In fact,
silicon is an essential nutrient for the human body.
• However, silicon in the form of silica (silicon dioxide, SiO2) can be
harmful if inhaled in large amounts.
• It can be harmful if proper safety measures are not followed so it is
important to take proper precautions to minimize exposure

10. THANKYOU