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• The halogens are a chemical series.

•

They are the elements in Group 17 (oldstyle: VII or VIIA) of the periodic table: fluorine (F), chlorine (Cl), bromine (Br), iodine (I), astatine (At) and the as yet undiscovered ununseptium (Uus). The term halogen was coined to mean elements which produce salt in union with a metal. It comes from 18th century scientific French nomenclature based on erring adaptations of Greek roots. These elements are diatomic molecules in their natural form. They require one more electron to fill their outer electron shells, and so have a tendency to form a singlycharged negative ion. This negative ion is referred to as a halide ion; salts containing these ions are known as halides.

• Halogens are highly reactive, and as

such can be harmful or lethal to biological organisms in sufficient quantities. Halide ions combined with single hydrogen atoms form the hydrohalic acids (i.e., HF, HCl, HBr, HI), a series of particularly strong acids. (HAt, or "hydrastatic acid", should also qualify, but it is not typically included in discussions of hydrohalic acid due to astatine's extreme instability toward alpha decay.)

FLOURINE  Atomic

Symbol: F  Atomic Number:9  Atomic Weight: 18.998403  From the Latin and French words for flow, fluere.

History Of Discovery • Fluorine in the form of fluorspar (also called fluorite) ( calcium fluoride) was described in 1530 by Georgius Agricola for its use as a flux [1], which is a substance that is used to promote the fusion of metals or minerals. In 1670 Schwanhard found that glass was etched when it was exposed to fluorspar that was treated with acid. Karl Scheele and many later researchers, including Humphry Davy, Gay-Lussac, Antoine Lavoisier, and Louis Thenard all would experiment with hydrofluoric acid, easily obtained by treating calcium fluoride (fluorspar) with concentrated sulfuric acid. • It was eventually realized that hydrofluoric acid contained a previously unknown element. This element was not isolated for many years after this due to its extreme reactivity - it is separated from its compounds only with difficulty and then it immediately attacks the remaining materials of the compound. Finally, in 1886, fluorine was isolated by Henri Moissan after almost 74 years of continuous effort. It was an effort which cost several researchers their health or even their lives, and for Moissan, it earned him the 1906 Nobel Prize in chemistry.

• The first large scale production of fluorine was needed for the atomic bomb Manhattan project in World War II where the compound uranium hexafluoride (UF6) was used to separate the 235U and 238U isotopes of uranium. Today both the gaseous diffusion process and the gas centrifuge process use gaseous (UF6) to produce enriched uranium for nuclear power applications. • The derivation of elemental fluorine from hydrofluoric acid is exceptionally dangerous, killing or blinding several scientists who attempted early experiments on this halogen. These men came to be referred to as "Fluorine Martyrs."

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General Description • Fluorine is the most electronegative and reactive of all elements. It is a pale yellow, corrosive gas, which reacts with most organic and inorganic substances. Finely divided metals, glass, ceramics, carbon, and even water burn in fluorine with a bright flame. • Flourine is so dangerous that it must be stored in steel containers, and even then it reacts with the steel. Fortunately the layer of flouride that is formed is unreactive, and prevents it from reacting further. • Flourine is the most reactive element in the world. It reacts with absolutely everything (except for nitrogen, oxygen and some of the lighter noble gases), very often explosively. • Flourine attacks and breaks down most organic compounds which burn in it's pale yellow gas. .

Chemical Properties • • • • • • • •

Electrochemical Equivalent: 0.70883g/amp-hr Electron Work Function: Electronegativity (Pauling): 3.98 Heat of Fusion: 0.2552kJ/mol Incompatiblities: Water, nitric acid, oxidizers, organic compounds Ionization Potential First: 17.422 Second: 34.97 Third: 62.707 • valence Electron Potential (-eV): -10.1

Physical Properties • • • • • • • • • • • • • • • •

Atomic Mass Average: 18.9984 Boiling Point: 85.10K -188.05°C -306.49°F Coefficient of Linear Thermal Expansion: Conductivity Electrical: Thermal: 0.000279 W/cmK Density: 1.696g/L @ 273K & 1atm Enthalpy of Atomization: 79.08 kJ/mole @ 25°C Enthalpy of Fusion: 0.26 kJ/mole Enthalpy of Vaporization: 3.31 kJ/mole Flammablity Class: Non-flammable gas (extreme oxidizer) Freezing Point: see melting point Heat of Vaporization: 3.2698kJ/mol Melting Point: 53.63K -219.52°C -363.14°F Molar Volume: 17.1 cm3/mole Optical Refractive Index: 1.000195 Specific Heat: 0.82J/gK

Uses and Importance • Flourine in the form of flourochloro hydrcarbons are widely used in air conditioning and refrigeration, • Fluorine and its compounds are used in creating isotopically fractionated uranium. • Commercial fluorochemicals, used for creating high temperature plastics. • Hydrofluoric acid is often used during etching of glass for light bulbs and similar products. • Flouride is often included in water or tooth paste to assist in the fight again tooth decay, however not all countries through the world include Flouride in their water supplies.

• Flourine is used as hydroflouric acid in aluminium smelting and steel production, and Cryolite (a naturally accuring Flourine source) is used in Aluminium manufacture. Silicoflouride salts are used mainly in water flouridation and laundry detergents. • In much higher concentrations, sodium fluoride has been used as an insecticide, especially against cockroaches. • Without flourine, you'd have no recyclable cans, no cars chassis', your clothes would be filthy, and water wouldn't be safe to drink.

Other Facts • Both fluorine and HF must be handled with great care and any contact with skin and eyes should be strictly avoided. All equipment must be passivated before exposure to fluorine. • Contact with exposed skin may result in the HF molecule rapidly migrating through the skin and flesh into the bone where it reacts with calcium permanently damaging the bone, followed by cardiac arrest brought on by sudden chemical changes within the body. • Both elemental fluorine and fluoride ions are highly toxic. When it is a free element, fluorine has a characteristic pungent odor that is detectable in concentrations as low as 20 nL/L. It is recommended that the maximum allowable concentration for a daily 8-hour time-weighted exposure is 1 µL/L (part per million by volume) (lower than, for example, hydrogen cyanide).

Atomic Structure • Number of Energy Levels: 2 • First Energy Level: 2 • Second Energy Level: 7

Chlorine • Symbol: Cl • Atomic number: 17 • from the Greek language chloros, meaning "pale green"

History of Discovery • Chlorine was discovered in 1774 by Swedish chemist Carl Wilhelm Scheele, who called it dephlogisticated marine acid (see Phlogiston theory) and mistakenly thought it contained oxygen. Chlorine was given its current name in 1810 by Sir Humphry Davy, who insisted that it was in fact an element. • Chlorine gas, also known as bertholite, was first used as a weapon against human beings in WWI on April 22nd, 1915, and afterwards was used by both sides.

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General Description • Chlorine is a greenish yellow gas which combines directly with nearly all elements. Chlorine is a respiratory irritant. The gas irritates the mucous membranes and the liquid burns the skin. As little as 3.5 ppm can be detected as an odor, and 1000 ppm is likely to be fatal after a few deep breaths. It was used as a war gas in 1915. It is not found in a free state in nature, but is found commonly as NaCl (solid or seawater). • Chlorine, Cl2, reacts with water to produce hypochlorite, OCl-. The position of the equilibrium depends very much upon the pH of the solution. • This element is a member of the salt-forming halogen series and is extracted from chlorides through oxidation and more commonly, by electrolysis.

• As the chloride ion, which is part of common salt and other compounds, it is abundant in nature and necessary to most forms of life, including humans. As chlorine gas, it is greenish yellow, is two and one half times as heavy as air, has an intensely disagreeable suffocating odor, and is exceedingly poisonous. In its liquid and solid form it is a powerful oxidizing, bleaching, and disinfecting agent.

Chemical Properties • • • • • •

Electrochemical Equivalent: 1.3228g/amp-hr Electron Work Function: Electronegativity (Pauling): 3.16 Heat of Fusion: 3.203kJ/mol Incompatiblities: Reacts explosively or forms explosive compounds with many common substances such as acetylene, ether, turpentine, ammonia, fuel gas, hydrogen & finely divided metals. • Ionization Potential • First: 12.967 Second: 23.81 Third: 39.611 • valence Electron Potential (-eV): -7.96

Physical Properties • • • • • • • • • • • • • • • • • • •

Atomic Mass Average: 35.4527 Boiling Point: 239.3K -33.9°C -29°F Coefficient of Linear Thermal Expansion: Conductivity Electrical: Thermal: 0.000089 W/cmK Density: 3.214g/L @ 273K & 1atm Elastic Modulus: Bulk: 1.1/GPa Enthalpy of Atomization: 121.8 kJ/mole @ 25°C Enthalpy of Fusion: 3.38 kJ/mole Enthalpy of Vaporization: 10.21 kJ/mole Flammablity Class: Non-flammable gas (strong oxidizer) Freezing Point: see melting point Heat of Vaporization: 10.2kJ/mol Melting Point: 172.31K -100.84°C -149.51°F Molar Volume: 18.7 cm3/mole Optical Refractive Index: 1.000773 Specific Heat: 0.48J/gK Vapor Pressure = 1300kPa

Uses and Importance • Chlorine became the first killing agent to be employed during World War I. German chemical conglomerate IG Farben had been producing chlorine as a by-product of their dye manufacturing. In cooperation with Fritz Haber of the Kaiser Wilhelm Institute for Chemistry in Berlin, they began developing methods of discharging chlorine gas against enemy trenches. • Chlorine is commonly used as an antiseptic and is used to make drinking water safe and to treat swimming pools. • Large amounts of chlorine are used in many industrial processes, such as in the production of paper products, plastics, dyes, textiles, medicines, antiseptics, insecticides, solvents and

Other Facts • Chlorine irritates respiratory systems especially in children and the elderly. In its gaseous state it irritates mucous membranes and in its liquid state it burns skin. It takes as little as 3.5 ppm to be detected as a distinct odor, but it takes 1000 ppm or more to be fatal. Because of this, chlorine was one of the gases used during World War I as a war gas

• Number of Energy Levels: 3 • First Energy Level: 2 • Second Energy Level: 8 • Third Energy Level: 7

Bromine  Symbol:

Br  Atomic Number:35  from Greek word Bromos meaning "stench"

History of discovery Bromine was discovered by Antoine J. Balard in France in 1826.

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General description Bromine is a chemical element in the periodic table that has the symbol Br and atomic number 35. A halogen element, bromine is a red volatile liquid at standard room temperature which has reactivity between chlorine and iodine. This element is corrosive to human tissue in a liquid state and its vapors irritate eyes and throat. Bromine vapors are very toxic upon inhalation.

Bromine is the only nonmetallic liquid element. It is a heavy, mobile, reddishbrown liquid, volatilizing readily at room temperature to a red vapor with a strong disagreeable odor, resembling chlorine, and having a very irritating effect on the eyes and throat; it is readily soluble in water or carbon disulfide, forming a red solution, is less active than chlorine but more so than iodine; it unites readily with many elements and has a bleaching action; when spilled on the skin it produces painful sores. It presents a serious health hazard, and maximum safety precautions should be taken when handling it.

Chemical properties: Atomic number: 35 Atomic mass: 79.904 g.mol-1 Density: 3.1 g.cm-3 at 20°C Melting point: -7.2°C Boiling point: 58.8°C

Physical properties Atomic Mass Average: 79.904 Boiling Point: 332.40K 59.25°C 138.65°F Coefficient of Linear Thermal Expansion: Conductivity Electrical: Thermal: 0.00122 W/cmK Density: 3.119g/cc @ 300K Elastic Modulus: Bulk: 1.9/GPa Enthalpy of Atomization: 111.7 kJ/mole @ 25°C

Enthalpy of Fusion: 5.29 kJ/mole Enthalpy of Vaporization: 15.46 kJ/mole Flammablity Class: Noncombustible Liquid Freezing Point: see melting point Heat of Vaporization: 15.438kJ/mol Melting Point: 266.1K -7.1°C 19.2°F Molar Volume: 25.62 cm3/mole Optical Refractive Index: 1.001132 Pysical State (at 20°C & 1atm): Liquid Realitive Gas Density (Air=1) = 5.51 Specific Heat: 0.473J/gK Vapor Pressure = [email protected]°C

Uses and importance: Gasoline antiknock mixtures Fumigants Poisons Dyes Photographic chemicals Medicinal Brominated vegetable oil

Atomic Structure Number of Energy Levels: 4 First Energy Level: 2 Second Energy Level: 8 Third Energy Level: 18 Fourth Energy Level: 7

IODINE I  Atomic Number: 53  Symbol:  From

the Greek word "iodes" meaning "violet".

History Of wasDiscovery discovered by

Iodine Barnard Courtois in 1811. He was the son of a manufacturer of saltpeter (potassium nitrate, a vital part of gunpowder). At the time France was at war and gunpowder was in great demand. Saltpeter was isolated from seaweed washed up on the coasts of Normandy and Brittany. To isolate the potassium nitrate, seaweed was burned and the ash then washed with water. The remaining waste was destroyed by adding sulfuric acid. One day Courtois added too much sulfuric acid and a cloud of purple vapor rose. Courtois noted that the vapor crystallized on cold surfaces making dark crystals. Courtois suspected that this was a new element but lacked the money to pursue his observations.

Charles Bernard Desormes (1777 - 1862) and Nicolas Clément (1779 - 1841) to continue research. He also gave some of the substance to Joseph Louis Gay-Lussac (1778 - 1850), a wellknown chemist at that time, and to André-Marie Ampère (1775 - 1836). On 29 November 1813 Dersormes and Clément made public Courtois’ discovery. They described the substance to a meeting of the Imperial Institute of France. On December 6 GayLussac announced that the new substance was either an element or a compound of oxygen. Ampère had given some of his sample to Humphry Davy (1778 - 1829). Davy did some experiments on the substance and noted its similarity to chlorine. Davy sent a letter dated December 10 to the Royal Society of London stating that he had identified a new element. A large argument erupted between Davy and GayLussac over who identified iodine first but both scientists acknowledged Barnard Courtois as the

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General Description OF Element Iodine is a dark-gray/purple-black solid that sublimes at standard temperatures into a purplepink gas that has an irritating odor. This halogen forms compounds with many elements, but is less active than the other members of its Group VII (halogens) and has some metallic-like properties. Iodine dissolves easily in chloroform, carbon tetrachloride, or carbon disulphide to form purple solutions (It is only slightly soluble in water, giving a yellow solution). The deep blue color of starch-iodine complexes is produced only by the free element.

 Iodine

is a solid diatomic non-metal that is very pungent in odor and a corrosive poison. Th density of iodine is 4.94 g/mL, which means it will sink in water.  Iodine, I2 is not reactive towards with oxygen, O2, or nitrogen, N2.  Iodine, I2, reacts with water to produce hypoiodite, OI-. The position of the equilibrium depends very much upon the pH of the solution.  In the graphic on the left, iodine element reacts with zinc metal to form zinc iodide. The reaction is so exothermic that part of the iodine element solid is vaporized to iodine violet gas.

Chemical Properties:        



Electrochemical Equivalent: 4.7348g/amp-hr Electron Work Function: Electronegativity (Pauling): 2.66 Heat of Fusion: 7.824kJ/mol Incompatiblities: Ammonia, acetylene, acetaldehyde, powdered aluminum, active metals, liquid chlorine Ionization Potential First: 10.451 Second: 19.131 Third: 33 valence Electron Potential (-eV): -6.55

Physical Properties:  Atomic

Mass Average: 126.9045  Boiling Point: 458.6K 185.4°C 365.7°F  Coefficient of Linear Thermal Expansion:  0.000093cm/cm/°C (0°C)  Conductivity  Electrical: 8.0E -16 106/cm Thermal: 0.00449 W/cmK  Density: 4.93g/cc @ 300K  Elastic Modulus:  Bulk: 7.7/GPa

 Enthalpy

of Atomization: 106.7 kJ/mole @

25°C  Enthalpy of Fusion: 7.76 kJ/mole  Enthalpy of Vaporization: 20.88 kJ/mole  Flammablity Class: Non-combustible solid  Freezing Point: see melting point  Heat of Vaporization: 20.752kJ/mol  Melting Point: 386.7K 113.5°C 236.3°F  Molar Volume: 25.74 cm3/mole  Pysical State (at 20°C & 1atm): Solid  Specific Heat: 0.214J/gK

Use and Importance  In

areas where there is little iodine in the diet— typically remote inland areas and semi-arid equatorial climates where no marine foods are eaten—iodine deficiency gives rise to goiter, so called endemic goiter.  In some such areas, this is now combatted by the addition of small amounts of iodine to table salt in form of sodium iodide, potassium iodide, potassium iodate—this product is known as iodized salt.  Iodine compounds have also been added to other foodstuffs, such as flour, in areas of deficiency.  Iodine deficiency is the leading cause of preventable mental retardation. This is caused by lack of thyroid hormone in the infant. Iodine deficiency remains a serious problem that affects people around the globe.

 Uncombined

(elemental) iodine is mildly toxic to all living things.  iodide, and thyroxin which contains iodine, are used internally in medicine.  A solution of KI and iodine in alcohol is used as a disinfectant for external wounds.  Silver iodide is used in photography  added to table salt for nutrition to stop goiter in the thyroid  deep blue color in a starch solution is a sign of the free element  Iodine is primarily used in medicine, photography and in dyes.

Other Facts 



Direct contact with skin can cause lesions, so it should be handled with care. Iodine vapor is very irritating to the eye and to mucous membranes. Concentration of iodine in the air should not exceed 1 mg/m³ (eight-hour timeweighted average). When mixed with ammonia, it can form nitrogen triiodide which is extremely sensitive and can explode unexpectedly. The United States Food and Drug Administration recommends (21 CFR 101.9 (c)(8)(iv)) 150 micrograms of iodine per day for both men and women. Natural sources of iodine include seaweed, such as kelp and seafood. Salt for human consumption is often

Atomic Structure 

Number of Energy Levels: 5



First Energy Level: 2



Second Energy Level: 8



Third Energy Level: 18



Fourth Energy Level: 18



Fifth Energy Level: 7

Astatine  SYMBOL:

At  Atomic number: 85.  Astatine (after Greek αστατος astatos, meaning "unsteady")

History of Discovery The existence of "eka-iodine" had been predicted by Mendeleev. Astatine was first synthesized in 1940 by Dale R. Corson, K. R. MacKenzie, and Emilio Segrè at the University of California, Berkeley by barraging bismuth with alpha particles. An earlier name for the element was alabamine (Ab).

PICTURE

General Description of Discovery  Astatine has the most metallic-like

properties of any of the halogens.  Astatine is irritating to element collectors. Collecting all the man-made elements is of course impossible, since there are an open-ended number of them of increasingly short half-life. So people like to define a "complete" element collection as one containing all the elements up to uranium.

Chemical Properties        

Electrochemical Equivalent: 7.8346g/amp-hr Electron Work Function: Electronegativity (Pauling): 2.2 Heat of Fusion: 114kJ/mol Incompatiblities: Ionization Potential First: 9.65 valence Electron Potential (-eV):

Physical Properties           

Atomic Mass Average: 210 Boiling Point: 610K 337°C 639°F Coefficient of Linear Thermal Expansion: Conductivity Electrical: Thermal: 0.017 W/cmK Enthalpy of Atomization: 92 kJ/mole @ 25°C Flammablity Class: Freezing Point: see melting point Heat of Vaporization: kJ/mol Melting Point: 575K 302°C 576°F Pysical State (at 20°C & 1atm): Solid

Use and Importance  Astatine is produced by bombarding

bismuth with energetic alpha particles to obtain relatively long-lived 209At - 211At, which can then be distilled from the target by heating in the presence of air.

Other Facts  Astatine is highly carcinogenic: Mammary

and pituitary tumors have been induced in laboratory animals by a single injection.  Astatine can be produced by bombarding bismuth with energetic alpha particles to obtain the relatively long-lived 209-211At, which can be distilled from the target by heating in air.

Atomic Structure Number of Energy Levels: 6  First Energy Level: 2 



Second Energy Level: 8



Third Energy Level: 18



Fourth Energy Level: 32



Fifth Energy Level: 18



Sixth Energy Level: 7