Trent SmithMr. EvansChemistry12/05/2017Silicon Devices like the iPhone are used all around the world by many people everyday. The world runs on technology. Without silicon, however, none of this would be possible. Silicon is an important element and is depended on by us to live our everyday lives. Silicon is number 14 on the periodic table. It has an atomic weight of 28.0855. It is a solid and is classified as a semi-metal. Jons Jacob Berzelius first discovered silicon in 1824. He discovered silicon by taking chips of potassium and heating them up in a silica container. Once that was finished, he carefully washed the residual by-products away until a brown powder was formed. Silicon is the seventh most abundant element that is found in the universe. It is also the second most abundant element that can be found in the crust of the Earth. By heating carbon with sand, silicon can be produced. However, heating must reach temperatures as high as 2200 degrees celsius. Two allotropes (which are each of two or more different physical forms in which an element can exist) of silicon exist at room temperature. These are amorphous and crystalline. Amorphous silicon is seen as a brown powder, like the one Berzelius discovered. Crystalline silicon, on the other hand, has a metallic luster and a grayish color. Through the Czochralski process,people are able to grow crystals of crystalline silicon. These crystals, when doped with elements such as boron, gallium, germanium, phosphorus or arsenic, are to produce solid-state electronic devices, such as transistors, solar cells, rectifiers and microchips. Silicon dioxide, which is silicon’s most common compound, is the most abundant compound that can be found in the crust of the Earth. It most commonly takes on the form of ordinary sand, but it is also able to exist as quartz, rock crystal, amethyst, agate, flint, jasper and opal. Glass and bricks, when manufactured, use silicon dioxide. Silica gel has the ability to absorb moisture and is used by many as a desiccant. Many useful compounds that are formed include silicon. Silicon carbide, which has hardness comparable to a diamond, is used most commonly as an abrasive. Sodium silicate, which many refer to as water glass, is used in the production of soaps, adhesives and is even also used as an egg preservative. Silicon tetrachloride is crucial for the creation and usage of smoke screens. Silicone uses silicon as a main ingredient in its production as well. Silicone is a class of material that is used for objects like lubricants, polishing agents, electrical insulators and medical implants. 2 Silicon is able undergo many reactions. It has various reactions with air. The surface on lumps of silicon are protected by a layer of silicon dioxide, which is SiO2. This makes silicon immobile to further oxidation by air even up to temperatures of 900°C. After these temperatures, reactions with oxygen in the air produce silicon dioxide. At temperatures above 1400°C, silicon reacts with nitrogen, which is N2, in the air as well as with oxygen, to form the silicon nitrides SiN and Si3N4.Si(s) + O2(g) ? SiO2(s)2Si(s) + N2(g) ? 2SiN(s)3Si(s) + 2N2(g) ? Si3N4(s)It does not have any reactions with water. The surface of lumps of silicon is protected by a very thin layer of silicon dioxide, SiO2. This makes silicon inert to water and even inert to steam. It does react with halogens. Silicon reacts with all the halogens. These reactions form silicon tetrahalides. That means it reacts with fluorine, F2, chlorine, Cl2, bromine, Br2, and iodine, I2, to form , respectively, silicon(IV) fluoride(SiF4), silicon(IV) chloride (SiCl4), silicon(IV) bromide (SiBr4), and silicon(IV) iodide (SiI4). The reaction with fluorine takes place at room temperature as opposed to the others, which require warming over 300°C.Si(s) + 2F2(l) ? SiF4(g)Si(s) + 2Cl2(l) ? SiCl4(g)Si(s) + 2Br2(l) ? SiBr4(l)Si(s) + 2I2(l) ? SiI4(s)Silicon does not react with most acids under normal conditions but is dissolved by hydrofluoric acid, HF, a reaction driven by the stability of the Si(IV) fluoride complex SiF62-.Si(s) + 6HF(aq) ? SiF62-(aq) + 2H+(aq) + 2H2(g)Silicon is attacked by bases such as aqueous sodium hydroxide to give silicates, which are highly complex species containing the anion SiO44-.Si(s) + 4NaOH(aq) ? SiO44-(aq) + 4Na+(aq) + 2H2(g) 1Perhaps silicon is mostly used and depended on for technological processes. This use of silicon has the biggest effect on our everyday lives. High-purity silicon is manufactured by thermally decomposing the ultra-puren inorganic compound trichlorosilane. This process is then followed by silicon’s recrystallisation, which is used to create many types of electronics, including semiconductors, transistors, printed circuit boards, and integrated circuits. For transistors, the material is doped by adding in a small impurity which lets the electrons to move around, conduct electricity, and create reliable semiconductors for voltage. When heated into a molten state, silicon can be formed into semiconductive wafers to serve as the base for integrated circuits, or microchips. 4 A microchip is a device that forms the brains of every computing device. While chips appear to be flat, they are three-dimensional structures and may include as many as 30 layers of complex circuitry. 3 Without silicon, the electronics that we use in our lives would not be able to function correctly and the structure of the world would collapse, as there would be no way to continue to function in a technology centered society. Silicon has impacted the lives of all of us more than we give it credit for.