Let's do some revision! (PART 1)

Baiklah...

Tiba-tiba hari ni mood nak ulangkaji balik subjek CHEMISTRY...

Haih~ Banyak aku lupa... Baru berapa bulan tinggalkan sekolah...

Tapi aku cuma nak tahu tentang kegunaan setiap 'element' yang ada dalam 'periodic table' ...

Tu je lah yang aku terasa nak tahu pon.... (Aku saja je nih) Haha...

So, apa lagi... Google lah! Hoho...

Sumber : chemwiki.ucdavis.edu

Pelik... kenapa periodic table dia tak sama macam yang aku tengok selama ni?
Apa-apa jelah...

Group 1 - Alkali metals

Group 2 - Alkaline Earth Metals

Group 3 - Transition Metals

Group 4 - Transition Metals

Group 5 - Transition Metals

Group 6 - Transition Metals

Group 7 - Transition Metals

Group 8 - Transition Metals

Group 9 - Transition Metals

Group 10 - Transition Metals

Group 11 - Transition Metals

Group 12 - Transition Metals

Group 13 - Boron Family

Group 14 - Carbon Family

Group 15 - Nitrogen Family

Group 16 - Oxygen Family

Group 17 - Halogens

Group 18 - Noble Gases

HYDROGEN!

• Hydrogen is a nonmetal.  It is placed above group in the periodic table because it has ns¹ electron configuration like the alkali metals.  However, it varies greatly from the alkali metals as it forms cations (H⁺) more reluctantly than the other alkali metals.  Hydrogen‘s ionization energy is 1312 kJ/mol, while lithium (the alkali metal with the highest ionization energy) has an ionization energy of 520 kJ/mol.
• Because hydrogen is a nonmetal and forms H^- (hydride anions), it is sometimes placed above the halogens in the periodic table.  Hydrogen also forms H₂ dihydrogen like halogens.  However, hydrogen is very different from the halogens.  Hydrogen has a much smaller electron affinity than the halogens.    
• H₂ dihydrogen or molecular hydrogen is non-polar with two electrons.  There are weak attractive forces between H₂ molecules, resulting in low boiling and melting points.  However, H₂ has very strong intramolecular forces; H₂ reactions are generally slow at room temperature due to strong H—H bond.  H₂ is easily activated by heat, irradiation, or catalysis.  Activated hydrogen gas reacts very quickly and exothermically with many substances. 
• Hydrogen also has an ability to form covalent bonds with a large variety of substances. Because it makes strong O—H bonds, it is also considered a good reducing agent for metal oxides.  Example: CuO(s) + H₂(g) → Cu(s) + H₂O(g) H₂(g) passes over CuO(s) to reduce the Cu²⁺ to Cu(s), while getting oxidized itself.
• Hydrogen is very important to the world. About 70% of the hydrogen produced is used in the Haber process, which is a process of fixing nitrogen gas into ammonia (a usable form by plants).  Without the Haber process, we would not be able to grow the huge amounts of crops we grow today.
• Hydrogen is also used for the hydrogenation of oils.Hydrogenation entails replacing double bonds in oils by hydrogen, converting the double bonds into single bonds.  This transformation of unsaturated fats to saturated fats drastically increases the shelf life of many foods.  However, an increased consumption of saturated fats has been linked to greater visible for heart disease, high cholesterol, and certain types of cancer. 
• Because hydrogen is a good reducing agent, it is used to produce metals like iron, copper, nickel, and cobalt from their ores.  
• Liquid hydrogen (combined with liquid oxygen) is a major component of rocket fuel (as mentioned above combination of hydrogen and oxygen relapses a huge amount of energy).  
• Because one cubic feet of hydrogen can lift about .07 lbs, hydrogen lifted airships or Zeppelins became very common in the early 1900s.However, the use of hydrogen for this purpose was largely discontinued around World War II after the explosion of The Hindenburg. The Hindenburg prompted greater use of inert helium, rather than flammable hydrogen for air travel.
  
  

HELIUM

• Helium is the second most abundant element in the universe, next to hydrogen. Helium is colorless, odorless, and tasteless. It has very low boiling point, and is always monoatomic. Helium is very small and extremely light. It is the least reactive of all elements; it does not react with any other elements or ions, which result in no helium-bearing minerals in nature. Helium was first observed by studying the Sun, and was named after the Greek word for Sun, Helios.
•  Helium is one of the most abundant element in the universe. Great quantities are found in the energy-producing fusion reactions in stars. Previously, helium was rarely used, because only .0004% of Earth's atmosphere is helium. There is only one helium molecule out of every 200,000 air molecules, including oxygen, hydrogen, and nitrogen. However, the discovery of helium-rich wells in Texas, Russia, Poland, Algeria, China, and Canada made helium more accessible.
•  Helium is contained in minerals as product of radioactive decay. Helium is extracted from natural gas deposits, which often contain as much as 10% helium.  These natural gas reserves are the single source of helium. It is believed that the total world helium resources add up to 25.2 billion cubic meters and U.S. alone has 11.1 billion cubic meters of those helium resources. The extracted gas is put through chemical pre-purification with alkaline wash to remove carbon dioxide and hydrogen sulfide. The remaining gas is cooled to -200°C, where all substance, except helium gas, is liquefied.
•  Helium has a number of applications due to its inert nature. Liquefied helium is used in cryogenics where biological materials are frozen with liquid helium for long term storage and later use. 20% of helium used is in wielding and industrial applications. Helium protects the heated parts of metal, like aluminum and titanium, from attack by air. Helium and oxygen mixtures are used in tanks for underwater breathing devices. Due to its low density, it allows oxygen to stream easily through the lungs. Because helium remains as gas, even in low temperature of liquid hydrogen, it is used as pressure gas to move liquid hydrogen into rocket engines. Its inert nature also makes helium useful for cooling nuclear power plants.
•  The most commonly known characteristic of helium is that it is lighter than air. It can hold up balloons during parties and fly blimps over sports stadiums. It has 92% lifting power of that of hydrogen, however it is safer since it is not combustible, and it has lower diffusion than that of hydrogen gas. The famous Hindenburg disaster is an example of those dangers in using combustible gas, such as hydrogen. Because helium was very expensive in the past, and was only available from natural gas reserves in U.S., the Nazi Germany was only left with high quantified, but less qualified hydrogen. The consequence was devastating.
•  In modern days, helium has been found in other natural gas reserves around the world. The cost of helium has gone down from $2500/ft³ in 1915 to $0.15/ft³ in 1989. Helium is what keeps those Good-year blimps afloat over stadiums.
•  In parties, helium is often inhaled from balloons to produce squeaky voice. Though it is quite amusing, it can be very harmful. Inhaling helium can lead to loss of consciousness and cerebral arterial gas embolism, which can temporarily lead to complete blindness. Blood vessels in the lungs will first rupture and allow the gas to gain access to the pulmonary vasculature and subsequently the brain.

LITHIUM

• Lithium is a rare element found primarily in molten rock and saltwater in very small amounts.  It is understood to be non-vital in human biological processes, although it is used in many drug treatments due to its positive effects on the human brain. Because of its reactive properties, humans have utilized lithium in batteries, nuclear fusion reactions, and thermonuclear weapons. 
•  Lithium's identification first came when it was found to be a part of the mineral Petalite. It was discovered by chemist Yohan August Arfwedson when he was analyzing the Petalite ore. Lithium is on the first column of the Periodic Table, thus making Lithium an alkali metal with the atomic number = 3 and an atomic mass of 6.941 g/mol. This means that Lithium has 3 protons, 3 electrons and 4 neutrons (6.941 - 3 = ~4). Being an alkali metal, Lithium is a soft, flammable, and highly reactive metal that tends to form hydroxides. It also has a pretty low density. When Lithium is in standard conditions, it is the least dense solid element.
•  Lithium is able to be used in the function of a Lithium battery in which the Lithium metal serves as the anode. Lithium ions serve in lithium ion batteries (chargeable) in which the lithium ions move from the negative to positive electrode when discharging, and vice versa when charging.
•  Lithium has the highest specific heat capacity of the solids, Lithium tends to be used as a cooler for heat transfer techniques and applications.

BERYLLIUM

• Beryllium is an element found in nature and is combined with other elements in minerals, including beryl and chrysoberyl.  In its purest form, beryllium is a steel-gray and lightweight alkaline earth metal.  
•  Due to its physical properties, beryllium is useful as a hardening agent in alloys, making aerospace material, and used as a filter for radiation.  Beryllium is not used for commercial use due to the harmful effects when it is inhaled through dust particles, causing berylliosis (a corrosive disease typically in the lungs).  Beryllium is a rare element on Earth and in the universe and is not found to be necessary or helpful for plants or animals.  
• Beryllium is in approximately 100 of the 4000 known minerals, such as bertrandite, beryl, chrysoberyl, and phenakite.  Beryllium is also present in precious gems such as aquamarine, bixbite, and emerald. Of the many beryllium minerals, only two are of commercial importance in the preparation of beryllium metal and its compounds.  Bertrandite (Be₄Si₂O₇(OH)₂) contains less than 1% Be and is the main beryllium mineral mined in the U.S., while beryl (Be₃Al₂(SiO₃)₆ is mined in other countries and contains approximately 4% Be.  In the U.S., beryllium is mainly mined at Gold Hill and Spor Mountain in Utah, and in Alaska on the Seward Peninsula.   
•  Beryllium metal began commercial production in 1957, but did not live up to its expectation of expanding the industry.  Beryllium is made by reducing beryllium fluoride with magnesium metal in the following equation:
  {BeF_2 + Mg \rightleftharpoons MgF_2 + Be}
• Emerald is less common than diamond and more expensive than gold. Columbia produces the most emerald in the world, where the Muzo mine and eastern emerald belt are located.

• Despite having problems of beryllium being brittle, pricey, and poisonous, it still has many valuable purposes. Its light weight, non-magnetic properties, and reluctance to spark is great for non-sparking tools.  Beryllium is great for making aircraft and space ships due to its low density, high heat capacity, and high modulus of elasticity.
•  With a simple nuclei of just 4 protons and 5 neutrons, beryllium is great for tubes as it allows all radiation to pass through easily.  On the contrary, beryllium atoms reflect neutrons making it great for reflectors, moderators, and control rods in research reactors. Beryllium oxide is a great electric insulator and heat conductor.  It is transparent to microwaves making it useful in microwave communications systems.  Beryllium oxide is also used in computers, lasers, and automotive ignition systems.

BORON

• Boron is the fifth element of the periodic table, located in Group 13.  It is classified as a metalloid due it its ambiguous properties that reflect a combination of both metals and nonmetals.  
• Boron is the only element in its group that is not a metal. It has properties that lie between metals and non-metals (semimetals). For example Boron is a semiconductor unlike the rest of the group 13 elements. Chemically, it is closer to aluminum than any of the other group 13 elements.
•  Many boron compounds are electron-deficient, meaning that they lack an octet of electrons around the central boron atom. This deficiency is what accounts for boron being a strong Lewis acid, in that it can accept protons (H⁺ ions) in solution.  Boron-hydrogen compounds are referred to as boron hydrides, or boranes.
•  Although boron compounds are widely distributed in Earth's crust, a few concentrated ores are located in Italy, Russia, Tibet, Turkey, and California. Borax is the most common ore found, and it can be turned into a variety of boron compounds. When a solution of borax and hydrogen peroxide is crystallized, sodium perborate (NaBO₃ * 4 H₂O) is formed. Sodium perborate is used in color-safe bleaches.
•  The key to the bleaching ability of this compound is the presence of its two peroxo groups that bridge the boron atoms together. Another compound that other boron compounds can be synthesized from is boric acid (B(OH)₃). When mixed with water, the weakly acidic and electron deficient boric acid accepts an OH- ion from water and forms the complex ion [B(OH)₄]-.
•  Borate salts produce basic solutions that are used in cleaning agents. Boric acid is also used as an insecticide to kill roaches, and as an antiseptic in eyewash solutions. Other boron compounds are used in a variety of things, for example: adhesives, cement, disinfectants, fertilizers, fire retardants, glass, herbicides, metallurgical fluxes, and textile bleaches and dye.

CARBON

• Organic chemistry involves structures and reactions of mainly carbon and hydrogen. Inorganic chemistry deal with interactions of all other pure elements besides carbon, amongst geo/biochemistry.  So where does inorganic chemistry of carbon fit in?  The inorganic chemistry of carbon also known as inorganic carbon chemistry, is the chemistry of carbon that does not fall within the organic chemistry zone.

NITROGEN

• Nitrogen is present in almost all proteins and plays important roles in both biochemical applications and industrial applications. Nitrogen forms strong bonds because of its ability to form a triple bond with its self, and other elements. Thus, there is a lot of energy in the compounds of nitrogen. Before 100 years ago, little was known about nitrogen. Now, nitrogen is commonly used to preserve food, and as a fertilizer. 
•  Nitrogen is found to have either 3 or 5 valence electrons and lies at the top of Group 15 on the periodic table. It can have either 3 or 5 valence electrons because it can bond in the outer 2p and 2s orbitals. Nitrogen is not reactive at standard temprature and pressure. Nitrogen is a colorless, and odorless gas that is usually found in its molecular form of (N₂). For the most part, Nitrogen is inert. Nitrogen is a non-metal element that occurs most abundantly in the atmosphere, nitrogen gas (N₂) comprises 78.1% of the volume of the Earth’s air. It only appears in .002% of the earth's crust by mass.  Compounds of nitrogen are found in foods, explosives, poisons, and fertilizers. Nitrogen makes up DNA in the form of nitrogenous bases as well as in neurotransmitters. It is one of the largest industrial gases, and is produced commercially as a gas and a liquid.
• Nitrogen provides a blanketing for our atmosphere for the production of chemicals and electronic compartments.
• Nitrogen is used as fertilizer in agriculture to promote growth. 
• Pressurized gas for oil. 
• Refrigerant (such as freezing food fast)
• Explosives.
• Metals treatment/protectant via exposure to nitrogen instead of oxygen

OXYGEN

• Oxygen is an element that is widely known by the general public because of the large role it plays in sustaining life. Without oxygen, animals would be unable to breathe and would consequently die.
• Oxygen is not only important to supporting life, but plays an important role in many other chemical reactions. 

FLUORINE

• Fluorine (F) is the first element in the Halogen group (group 17) in the periodic table.  Its atomic number is 9 and its atomic weight is 19, and it's a gas at room temperature.  It is the most electronegative element, given that it is the top element in the Halogen Group, and therefore is very reactive.  It is a nonmetal, and is one of the few elements that can form diatomic molecules (F2).  It has 5 valence electrons in the 2p level.  Its electron configuration is 1s²2s²2p⁵.  It will usually form the anion F^- since it is extremely electronegative and a strong oxidizing agent. Fluorine is a Lewis acid in weak acid, which means that it accepts electrons when reacting.  Fluorine has many isotopes, but the only stable one found in nature is F-19. 
• Rocket fuels
• Polymer and plastics production
• teflon and tefzel production
• When combined with Oxygen, used as a refrigerator cooler
• Hydrofluoric acid used for glass etching
• Toothpaste
• Purify public water supplies
• Uranium production
• Air conditioning

NEON

• Neon is a member of the group 18 elements, the noble gases. This element is most commonly known through its use in glow lamps and advertising signs emitting a distinctive bright orange-red color. 
•  Neon is the fourth most abundant element in the entire universe, behind hydrogen, helium and oxygen. However, it is considered very rare on Earth as it can mainly be found in the atmosphere, which consists only 0.001818% of Neon in volume. This is because it is highly inert, very light, and has high vapor pressure at low temperatures. These properties explain why smaller, warmer, and solid planets like Earth are less abundant in Neon. Although, small traces of Neon can be encountered in the Earth's crust and ocean. Its estimated abundance is 5×10^-3 mg/Kg and 1.2×10^-4 mg/L respectively. Neon is the second lightest noble gas and is a monatomic gas, therefore found as Ne and not Ne₂.   
• Neon is most notable for its use in neon lighting and signs. These neon lights are made with filled glass or plastic tubes with Neon gas.  As electricity passes through these tubes, electric discharge produces high-energy electrons that hit the neon atoms changing their energy state, as photon of light is emitted. These glass tubings can be shaped and twisted to form various designs.
•  It is a common misconception that all “neon” lights are made entirely of neon, as they do not change colors. Tubes filled solely with the Ne (g) emit the bright orange-red color. The different colors of lights are made by mixing other noble gases and elements. Over 150 colors can be made. (Ex: Mercury emits a light blue color). Other commercial uses for Neon are in high-voltage indicators, TV tubes, lightning arresters, and helium-gas lasers. Also, liquid neon is used as an economical cryogenic refrigerant.

SODIUM

• Sodium is metallic element found in the first group of the periodic table. As the sixth most abundant element in the Earth's crust, sodium compounds are commonly found dissolved in the oceans, in minerals, and even in our bodies. 
•  Sodium is an element that is a member of the alkali metal group with a symbol Na. It is physically silver colored and is a soft metal of low density. Pure sodium is not found naturally on earth because it is a highly reactive metal. The sodium ion is abundantly found within the Earth's oceans, bodies of water, and many minerals. It is used for chemical synthesis, analysis, and heat transfer applications. Sodium is also a crucial element for animal and plant life by creating charge gradients and assisting in the development of energy. 
•  In metallic form, sodium can be used to refine reactive metals such as zirconium and potassium, improve alloy structures, descale metal and purify molten metals. It is often used as a desiccant for drying solvents in chemistry and is also used as a reducing agent in organic synthesis. The sodium fusion test uses sodium's physical properties to qualitatively analyze other compounds. 
  Sodium vapor lamps is also used for street lighting in cities. The low-pressure sodium lamps display a yellow-orange light from the predominantly sodium D lines. High pressure sodium lamps give a peach-colored light from the array of spectrum lines. 
  Sodium acts as a heat transfer fluid in some nuclear reactors and inside hollow valves of high-performance internal combustion engines.
• The sodium ion is vital to animal life because it maintains body fluid volumes and maintains electric potential in animal tissue. In soap, sodium is used as sodium salts of fatty acids because it is harder and higher melting than other soaps. In medicine, the salt form of a medication with high sodium or potassium ingredient can improve bioavailability. A compound of sodium and chloride (NaCl) is an important material for heat transfer.
•  Molten sodium is frequently used as a coolant in nuclear reactors. When the reactor is consistently running, a pure sodium coolant is used because sodium melts at about 98 °C. However, when the reactor is shut down, the sodium can melt the cooling pipes. Therefore, if the reactors need to be shut down often, the alloy of sodium and potassium is used because the compound melts at -11 °C so the cooling pipes will not freeze at room temperature. 
• The most common compound of sodium, sodium chloride, is used in food for seasoning and preservation. For example, common salt is used for pickling and making jerky. A healthy sodium intake for the human diet is about 1.5 grams per day. However, the intake of sodium for most people is typically ten times more than the necessary dietary amount.
• Sodium is important in the body, as it helps maintain body fluid homeostasis.  People with disorders that do not have enough sodium in the body can take medication such as serum sodium in order to maintain a healthy amount of sodium in the body.  Sodium is also crucial in osmotic pressure, as the body adjusts to when there is too little or too much sodium in the body.  Sodium is also the main cation in outside cells containing fluid in mammalian bodies, and very little sodium inside the cells, consisting of approximately 90% of the body's total sodium content.

MAGNESIUM

• Magnesium is a group two element and is the eighth most common element in the earth's crust.  Magnesium is light, silvery-white, and tough. Like aluminum, it forms a thin layer around itself to help prevent itself from rusting when exposed to air. Fine particles of magnesium can also catch on fire when exposed to air.  Magnesium is essential in nutrition for animals and plants. It is also used as an alloy to combine with other metals to make them lighter and easier to weld, for purposes in the aerospace industry along with other industries. It is also used in medicine, in the forms of magnesium hydroxides, sulfates, chlorides, and citrates. 
•  Magnesium is a strong metal that is light and silvery-white. Magnesium has the ability to tarnish,which is the ability to create an oxide layer around itself to prevent it from rusting. It also has the ability to react with water at room temperature. When exposed to water, bubbles form around the metal. Increasing the temperature speeds up this reaction. 
• One property of magnesium is high flammability. Like many other things, magnesium is more flammable when it has a higher surface area to volume ratio. An example of surface area to volume ratio is seen in the lighting of fire wood. It is easier to light kindling and smaller branches than a whole log. This property of magnesium is used in war, photography, and in light bulbs. Magnesium is used in war for incendiary bombs, flares, and tracer bullets. When these weapons are used, they ignite immediately and cause fires. The only way to extinguish a magnesium fire is to cover it with sand. Water does not extinguish the fire as water reacts with the hot magnesium and releases even more hydrogen.
•  Magnesium is one of the lightest metals, and when used as an alloy, it is commonly used in the automotive and aeronautical industries. The use of magnesium has increased and peaked in 1943. One reason the use of magnesium has increased is that it is useful in alloys. Alloys with magnesium are able to be welded better and are lighter, which is ideal for metals used in the production of planes and other military goods.
•  Another characteristic of magnesium is that it aids in the digestive process. Magnesium is commonly used in milk of magnesia and Epsom salts. These forms of magnesium can range from magnesium hydroxide, magnesium sulfate, magnesium chloride, and magnesium citrate. Magnesium not only aids in humans and animals, but also in plants. It is used to convert the sun's lights into energy for the plant in a process known as photosynthesis. The main component of this process is chlorophyll. This is a pigment molecule that is composed of magnesium. Without magnesium, photosynthesis as we know it would not be possible.

ALUMINIUM

• Aluminum, also called Aluminium, is the third most abundant element in the earth's crust.  It is commonly used in the household as aluminum foil, in crafts such as dyeing and pottery, and also in construction to make alloys.
•  Aluminum is the third most abundant element found on earth, and the most abundant metal.  It makes up 8.1% of the earth's crust by mass, following oxygen and silicon. Naturally, it is found in chemical compounds with other elements like bauxite. It is not easily removed from natural ores because it must first be reduced. To see how alumina, which is used to make aluminum, is extracted from bauxite, read the Bayer Process in the refining aluminum section.

SILICON

• Silicon, the second most abundant element on earth, is an essential part of the mineral world. Its stable tetrahedral configuration makes it incredibly versatile and is used in various way in our every day lives.  Found in everything from spaceships to synthetic body parts, silicon can be found all around us, and sometimes even in us.
•  Silicon is a group 14 element. It is in the same periodic group as carbon, but chemically behaves distinctly from all of its group counterparts. Silicon shares the bonding versatility of carbon, with its four valence electrons, but is otherwise a relatively inert element. However, under special conditions, silicon be made to be a good deal more reactive. Silicon exhibits metalloid properties, is able to expand its valence shell, and is able to be transformed into a semiconductor; distinguishing it from its periodic group members.
• Silicon is a vital component of modern day industry. Its abundance makes it all the more useful. Silicon can be found in products ranging from concrete to computer chips.
•  The high tech sectors adoption of the title Silicon Valley underscores the importance of silicon in modern day technology. Pure silicon, that is essentially pure silicon, has the unique ability of being able to discretely control the number and charge of the current that passes through it. This makes silicon play a role of utmost importance in devices such as transistors, solar cells, integrated circuits, microprocessors, and semiconductor devices, where such current control is a necessity for proper performance. Semiconductors exemplify silicon's use in contemporary technology. 
•  Semiconductors are unique materials that have neither the electrical conductivity of a conductor nor of an insulator. Semiconductors lie somewhere in between these two classes giving them a very useful property. Semiconductors are able to manipulate electric current. They are used to rectify, amplify, and switch electrical signals and are thus integral components of modern day electronics. 
  Semiconductors can be made out of a variety of materials, but the majority of semiconductors are made out of silicon. But semiconductors are not made out of silicates, or silanes, or silicones, they are made out pure silicon, that is essentially pure silicon crystal.  
  Like carbon, silicon can make a diamond like crystal. This structure is called a silicon lattice. (see Figure 15) Silicon is perfect for making this lattice structure because its four valence electrons allow it too perfectly bond to four of its silicon neighbors.
  However, this silicon lattice is essentially an insulator, as there are no free electrons for any charge movement, and is therefore not a semiconductor. This crystalline structure is turned into a semiconductor when it is doped. Doping refers to a process by which impurities are introduced into ultra pure silicon, thereby changing its electrical properties and turning it into a semiconductor. Doping turns pure silicon into a semiconductor by adding or removing a very very small amount of electrons, thereby making it neither an insulator nor a conductor, but a semiconductor with limited charge conduction. Subtle manipulation of pure silicon lattices via doping generates the wide variety of semiconductors that modern day electrical technology requires. 
  Semiconductors are made out of silicon for two fundamental reasons. Silicon has the properties needed to make semiconductors, and silicon is the second most abundant element on earth.
• Glass is another silicon derivate that is widely utilized by modern day society. If sand, a silica deposit, is mixed with sodium and calcium carbonate at temperatures near 1500 degrees Celsius, when the resulting product cools, glass forms. Glass is a particularly interesting state of silicon. Glass is unique because it represents a solid non-crystalline form of silicon. The tetrahedral silica elements bind together, but in no fundamental pattern behind the bonding.
•  Modern fiber optic cables must relay data via undistorted light signals over vast distances. To undertake this task, fiber optic cables must be made of special ultra-high purity glass. The secret behind this ultra-high purity glass is ultra pure silica. To make fiber optic cables meet operational standards, the impurity levels in the silica of these fiber optic cables has been reduced to parts per billion. This level of purity allows for the vast communications network that our society has come to take for granted. 
• Silicon plays an integral role in the construction industry. Silicon, specifically silica, is a primary ingredient in building components such as bricks, cement, ceramics, and tiles.
  Additionally, silicates, especially quartz, are very thermodynamically stable.  This translates to silicon ceramics having high heat tolerance. This property makes silicon ceramics particularily useful from things ranging from space ship hulls to engine components. 
•  Silicone polymers represent another facet of silicon's usefulness. Silicone polymers are generally characterized by their flexibility, resistance to chemical attack, impermeability to water, and their ability to retain their properties at both high and low temperatures. This array of properties makes silicone polymers very useful. Silicone polymers are used in insulation, cookware, high temperature lubricants, medical equipment, sealants, adhesives, and even as an alternative to plastic in toys. 
•  As silicon is not normally found in its pure state, silicon must be chemically extracted from its naturally occurring compounds. Silica is the most prevalent form of naturally occurring silicon. Silica is a strongly bonded compound and it requires a good deal of energy to extract the silicon out of the silica complex. The principal means of this extraction is via a chemical reaction at a very high temperature. 
•  The synthesis of silicon is fundamentally a two step process. First, use a powerful furnace to heat up the silica to temperatures over 1900 degrees celsius, and second, add carbon. At temperatures over 1900 degrees celsius, carbon will reduce the silica compound to pure silicon.
•  For some silicon applications, the purity of freshly produced silicon is not satisfactory. To meet the demand for high purity silicon, techniques have been devised to further refine the purity of extracted silicon. 
  Purification of silicon essentially involves taking synthesized silicon, turning it into a silicon compound that can be easily distilled, and then breaking up this new formed silicon compound to yield an ultra pure silicon product. There are several distinct purification methods available, but most chemical forms of purification involve both silane and silicon halide complexes.

PHOSPHORUS

• Phosphorus (P) is an essential part of life as we know it.  Without the phosphates in biological molecules such as ATP, ADP and DNA, we would not be alive. Phosphorus compounds can also be found in the minerals in our bones and teeth. It is a necessary part of our diet. In fact, we consume it in nearly all of the foods we eat. Phosphorus is quite reactive.  This quality of the element makes it an ideal ingredient for matches because it is so flammable. Phosphorus is a vital element for plants and that is why we put phosphates in our fertilizer to help them maximize their growth. 
•  Phosphorus plays a big role in our existence but it can also be dangerous. When fertilizers containing phosphorus enter the water, it produces rapid algae growth. This can lead to eutrophication of lakes and rivers. Eutrophication, means that the ecosystem has an increase of chemical nutrients and this can led to negative environmental effects.  With all the excess phosphorus, plants grow rapidly then die, causing a lack of oxygen in the water and an overall reduction of water quality. It is thus necessary to remove excess phosphorus from our wastewater. The process of removing the phosphorus is done chemically by reacting the phosphorus with compounds such as ferric chloride, ferric sulphate, and aluminum sulphate or aluminum chlorohydrate. Phosphorus, when combined with aluminum or iron, becomes an insoluble salt.  The solubility equilibrium constants of FePO₄ and AlPO₄ are 1.3x10^-22 and  5.8x10^-19, respectively. With solubility's this low, the resulting precipitates can then be filtered out.      
• Another example of the dangers of phosphorus is in the production of matches. The flammable nature and cheap manufacturing of white phosphorus made it possible to easily make matches around the turn of the 20th century. However, white phosphorus is highly toxic. Many workers in match factories developed brain damage and a disease called "phosphorus necrosis of the jaw" from exposure to toxic phosphorus vapors. Excess phosphorus accumulation caused their bone tissue to die and rot away.  For this reason, we now use red phosphorus or phosphorus sesquisulfide in "safety" matches.
• Phosphorus compounds are currently used in foods, toothpaste, baking soda, matches, pesticides, nerve gases, and fertilizers. Phosphoric acid is not only used in buffer solutions it is also a key ingredient of Coca Cola and other sodas! Phosphorus compounds were once used in detergents as a water softener until they raised concerns about pollution and eutrophication. Pure phosphorus was once prescribed as a medicine and an aphrodisiac until doctors realized it was poisonous (Emsley).

SULFUR

• Sulfur is a chemical element that is represented with the chemical symbol "S" and the atomic number 16 on the periodic table. Because it is 0.0384% of the Earth's crust, sulfur is the seventeenth most abundant element following strontium. Sulfur also takes on many forms, which include elemental sulfur, organo-sulfur compounds in oil and coal, H₂S(g) in natural gas, and mineral sulfides and sulfates. This element is extracted by using the Frasch process, a method where superheated water and compressed air is used to draw liquid sulfur to the surface. Offshore sites, Texas, and Louisiana are the primary sites that yield extensive amounts of elemental sulfur. However, elemental sulfur can also be produced by reducing H₂S, commonly found in oil and natural gas. For the most part though, sulfur is used to produce SO₂(g) and H₂SO₄. 
•  Sulfur has many practical applications. As a fungicide, sulfur is used to counteract apple scab in organically farmed apple production. Other crops that utilize sulfur fungicides include grapes, strawberries, and many vegetables. In general, sulfur is effective against mildew diseases and black spot. Sulfur can also be used as an organic insecticide. Sulfites are frequently used to bleach paper and preserve dried fruit.
•  The vulcanization of rubber includes the use of sulfur as well. Cellophane and rayon are produced with carbon disulfide, a product of sulfur and methane. Sulfur compounds can also be found in detergents, acne treatments, and agrichemicals. Magnesium sulfate (epsom salt) has many uses, ranging from bath additives to exfoliants. Sulfur is being increasingly used as a fertilizer as well. Because standard sulfur is hydrophobic, it is covered with a surfactant by bacteria before oxidation can occur. Sulfur is therefore a slow-release fertilizer. Lastly, sulfur functions as a light-generating medium in sulfur lamps. 
• Concentrated sulfuric acid was once one of the most produced chemicals in the United States, the majority of the H₂SO₄ that is now produced is used in fertilizer. It is also used in oil refining, production of titanium dioxide, in emergency power supplies and car batteries. The mineral gypsum is calcium sulfate dihydrate is used in making plaster of Paris. Over one million tons of aluminum sulfate is produced each year in the United States by reacting H₂SO₄ and Al₂O₃. This compound is important in water purification. Copper sulfate is used in electroplating. Sulfites are used in the paper making industry because they produce a substance that coats the cellulose in the word and frees the fibers of the wood for treatment.

CHLORINE

• Chlorine is a halogen in row 17 and period 3.  It is very reactive and is widely used for many purposes, such as as a disinfectant.   Due to its reactivity, it is commonly found in nature bonded to many different elements. 
•  Chlorine is used in the disinfection (removal of harmful microorganisms) of water and wastewater. In the United States, it is almost exclusively used.  Compared to other methods, it is effective at lower concentrations, and is inexpensive. Chlorine was first used to disinfect drinking water in 1908, using sodium hypochlorite (NaOCl):
  NaOCl+ H₂O → HOCl+NaOH
  Following widespread use of sodium hypochlorite to disinfect water, diseases caused by unclean water decreased greatly.  Disinfection is usually split into two stages; the first being the initial treatment that destroys and prevents the growth of algae and bacteria, and the second involving leaving some active agent that continues to prevent harmful pathogens from growing again. 

•  PVC(Polyvinyl Chloride) is a plastic which is widely manufactured throughout the globe, and is responsible for nearly a third of the world’s use of chlorine.  It is usually manufactured by first taking EDC(ethylene dichloride) and then making it into a vinyl chloride, the basic unit for PVC.  From then on, vinyl chloride monomers are linked together to form a polymer.  PVC becomes malleable at high temperatures, making it flexible and ideal for many purposes from pipes to clothing.  However, PVC is toxic.  When in gaseous form and inhaled, it can cause damage to the lungs, the body’s blood circulation, and nervous system. The production of PVC has many regulations surrounding it due to the many harmful effects that the plastic itself and the intermediates involved have on the environment and on human health.
•  Paper is one of the most widely consumed products in the world.  Before wood is made into a paper product, however, it must be turned into pulp (separated fibrous material).  This pulp has a color that ranges from light to dark brown.  Chlorine is used to bleach the pulp to turn it into a bright, white color, which makes it desirable for consumers. The process usually involves a number of steps, depending on the nature of the pulp.

PART 1 -TAMMAT-