Silicon

Introduction to What is Silicon

Silicon is a member of the carbon family and is a non-metallic chemical element, having atomic number 14 and belongs to group 14, period 3 in the p-block of the periodic table. Silicon is a metallic, one of the seven elements which have both the characteristics of non-metal and metal depending upon the other element to which it combines. Silicon used in electronics acts as metals, while the glass which is a silicon compound has non-metallic qualities. This element is denoted as 'Si'. Electronic configuration of silicon is [Ne] 3s2 3p2. The state of silicon is solid at 20°C. It is used in molding compounds.


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Symbol

Si

Atomic number

14

Atomic mass

28.0855 g/mol

Key Isotopes

28Si, 30Si

Electronic Configuration

[Ne] 3s2 3p2

Electronegativity

1.8

Oxidation State

-4,(+2),+4


Occurrence in Nature

Silicon is the second most abundant electropositive element which makes up 27.7% of the Earth's crust by mass. It occurs in combined form in nature as silicon dioxide which is commonly known as silica. About 97% of Earth's crust is made of rocks and comprises silicon and oxygen compounds. Silicon exists in nature in many dioxide forms, making compounds with oxygen, phosphorus, magnesium, and others. The minerals which contain silicon dioxide are known as silicates.


Properties of Silicon

Being a metalloid, Silicon also occurs in two allotropic forms. Allotropes are the element forms which have various chemical and physical properties.


Physical Properties of Silicon

  1. One silicon's allotrope is in the form of needle-like, shiny, greyish-black crystals or flat plates, while the other one has no crystal structure and it exists usually as a brown powder.

  2. The atomic number of silicon is 14 and its relative atomic mass is 28.085 u.

  3. The density of silicon is 2.3296 gram per cubic centimeter.

  4. The silicon melting point is 1,410°C and the silicon boiling point is 3,265°C.

  5. Silicon in its purest form is an intrinsic semiconductor. Although, adding impurities in small amounts helps in highly increasing the intensity of semiconductor.


Chemical Properties of Silicon

  1. Silicon is purely electropositive in its chemical behavior, has a metallic luster, and is considered to be very brittle.

  2. Silicon is very similar to metals in terms of chemical behavior.

  3. At room temperature, silicon is a relatively inactive element. Being solid, it does not combine with oxygen or other most related elements.

  4. Silicon is very reactive at higher temperatures.

  5. Silicon combines with oxygen, phosphorus, nitrogen, and other elements. It also forms alloys in the molten state.


Compounds/Polymers of Silicon(Silicon Materials)

  • Silanes:- Silanes are very strong reducing agents and consist of homologous series of compounds such as silicon hydrides. When exposed to air, these polymers are very reactive and can easily catch fire. At room temperature, they are unstable.

  • Silicides:- Silicides have similar structures to borides and carbides. Due to their similar structure, the heat of formation of these elements is similar. Silicon carbide is also known as Carborundum which is widely used as powdery material to polish or grind other material and has refractory properties.

  • Silica:- Silica (Silicon dioxide)  mainly consists of granite and sandstone which is used in the manufacture of glass, abrasives, in water filtration, as a food additive, and many more.

  • Halides:- Silicon compounds, mostly carbides form silicon tet halides when they react with stable halogens. Unlike carbon tetrahalides, these readily hydrolyze in water.

  • Silicic Acids:- Hydrated silica gels are formed as a result of increasing water concentration. Most silica gels are found to occur in an aqueous state.


Uses of Silicon

  1. Silicon is used in the production of ceramics, bricks, and fire bricks.

  2. Silicon is used to make many alloys such as aluminum-silicon and ferrosilicon known as iron-silicon which is widely used in the steel industry.

  3. Silicon is used to make polymers of silicon-oxygen with the methyl group attached known as silicones and its oil is a lubricant added in hair conditioner and cosmetics.

  4. Silicones rubber is used in waterproofing systems in bathrooms, roofs, and pipes.

  5. Being semiconductor, silicon is used in transistors and solid-state devices including microelectronics and computer industry.


Fun Facts

  1. In 1824, Silicon was discovered by Jons Jacob Berzelius.

  2. The atomic structure of silicon has 14 electrons having 4 electrons in the outermost shell (having the highest energy level), 8 electrons in the second orbit, and 2 electrons in the first orbit.


Silicon Boiling Point

By heating silicon dioxide, silicon is prepared which is 96 to 98% pure. Various applications of silicon require it in a pure form which is known as hyper-pure silicon. It’s considered to be 99.7% pure.

FAQ (Frequently Asked Questions)

1.Does Silicon Have Isotopes?

Yes, The element silicon has isotope. Silicon has a total of five known isotopes out of which three isotopes are found naturally. Silicon-28, Silicon-29, and Silicon-30 are the naturally occurring isotopes of silicon. Natural Silicon includes these three isotopes in 92.2% of silicon-28,  4.7% of  silicon-29, and 3.1% of silicon-30 respectively and all these isotopes are stable. Silicon-28 and Silicon-30 are considered as the key isotopes of silicon. Apart from the naturally occurring isotopes, silicon also has artificial radioactive isotopes which are very well known. These artificial radioactive isotopes of silicon have no commercial use.

2. What are the Health Effects of Silicon?

  1. Silicon dust affects the lungs that are slightly adverse and does not seem to produce critical toxic effects or organic disease in case they are exposed to exposure limits.

  2. Silicon has a possibility to cause chronic respiratory effects because Silicon dioxide (Crystalline silica) is a potent respiratory hazard.

  3. Silicon crystalline, on contact with eyes and skin, acts as an irritator. It leads to watering and redness of eyes due to irritation. Inhalation of silicon will cause irritation to the mucus membrane and lungs. Skin inflammation has characteristics of itching, reddening, and scaling.