In addition, chlorine is very useful in the pharmaceutical industry. Medicinal products containing chlorine are used to treat infections, allergies, and diabetes. The neutralized form of hydrochloride is a component of many medications. Chlorine is also used to sterilize hospital machinery and limit infection growth. In agriculture, chlorine is a component of many commercial pesticides: DDT dichlorodiphenyltrichloroethane was used as an agricultural insecticide, but its use was discontinued.
Bromine : Bromine is used in flame retardants because of its fire-resistant properties. It also found in the pesticide methyl bromide, which facilitates the storage of crops and eliminates the spread of bacteria.
However, the excessive use of methyl bromide has been discontinued due to its impact on the ozone layer. Bromine is involved in gasoline production as well. Other uses of bromine include the production of photography film, the content in fire extinguishers, and drugs treating pneumonia and Alzheimer's disease.
Iodine : Iodine is important in the proper functioning of the thyroid gland of the body. If the body does not receive adequate iodine, a goiter enlarged thyroid gland will form. Table salt now contains iodine to help promote proper functioning of the thyroid hormones. Iodine is also used as an antiseptic. Solutions used to clean open wounds likely contain iodine, and it is commonly found in disinfectant sprays.
In addition, silver iodide is important for photography development. Astatine : Because astatine is radioactive and rare, there are no proven uses for this halogen element. However, there is speculation that this element could aid iodine in regulating the thyroid hormones. Also, At has been used in mice to aid the study of cancer. Elements Fluorine - Fluorine has an atomic number of 9 and is denoted by the symbol F.
Table 1. Melting and Boiling Points increases down the group The melting and boiling points increase down the group because of the van der Waals forces. Ionization Energy d ecreases down the group If the outer valence electrons are not near the nucleus, it does not take as much energy to remove them. Electronegativity d ecreases down the group The number of valence electrons in an atom increases down the group due to the increase in energy levels at progressively lower levels.
Hydrogen Halides and Halogen Oxoacids Hydrogen Halides A halide is formed when a halogen reacts with another, less electronegative element to form a binary compound. Halogen Oxoacids A halogen oxoacid is an acid with hydrogen, oxygen, and halogen atoms.
States of Matter at Room Temperature Table 1. Oxidation States of Halogens in Compounds As a general rule, halogens usually have an oxidation state of Example 1. Solution Electronegativity increases across a period, and decreases down a group. Applications of Halogens Fluorine : Although fluorine is very reactive, it serves many industrial purposes.
III, Water solubilities and melting points of the alkali halogens. Fessenden, Elizabeth. Holbrook, Jack B. Kildahl, Nicholas K. Liprandi, Domingo A. Meek, Terry L. Practice Problems Why does fluorine always have an oxidation state of -1 in its compounds?
Which element s exist s as a solid in room temperature? Do the following increase or decrease down the group of halogens?
Answers Electronegativity increases across a period, and decreases down a group. Therefore, fluorine has the highest electronegativity out of all of the elements. Because fluorine has seven valence electrons, it only needs one more electron to acheive a noble gas configuration eight valence electrons.
Therefore, it will be more likely to pull off an electron from a nearby atom. References Hill, Graham, and John Holman. Chemistry in Context.
United Kingdom: Nelson Thornes, You can view more similar questions or ask a new question. Questions physicsl science Describe why atoms of bromine, Br, are so reactive. Similar Questions Science One molecule of bromine Br2 and two molecules of potassium KCl chloride combine in a reaction. Chemistry Bromine has two isotopes, Br- 79 and Br- Select all that chemistry when chlorine gas is bubbled into a solution of sodium bromide, the sodium bromide reacts to give bromine a red brown liquid and sodium chlorine.
Chemistry-Bonding2 :- Chlorine, Cl2, is a gas at room temperature, but bromine, Br2, is a liquid. Nonpolar molecules have a Chemistry A sample of 0, g of an ionic compound containing bromide ions Br- is dissolved in water and treated with excess of AgNO3.
If the mass of the precipitate of AgBr formed is 0, g, answer: a what percentage of bromine in chemistry A flask contains 0. Other major uses are in the manufacture of drilling fluids, pesticides, chemicals for the purification of water, photographic chemicals, and as an additive to rubber.
Compounds of bromine had been known for hundreds of years before the element was discovered. One of the most famous of these compounds was Tyrian purple, also called royal purple.
Tyrian comes from the word Tyre, an ancient Phoenician city. Only very rich people or royalty could afford to buy fabric dyed with Tyrian purple.
It was obtained from a mollusk shell fish found on the shores of the Mediterranean Sea a large body of water bordered by Europe, Asia, and Africa. He continued an experiment he had begun at home in which he added chlorine to spring water.
The addition of ether to that mixture produced a beautiful red color. A professor encouraged him by suggesting he study the substance in more detail. As these studies progressed, Balard published a report in a chemical journal that announced the discovery of the new element bromine. The two chemists had made the discovery at nearly the same time! Balard, however, is credited as the discoverer of bromine, because scientists acknowledge the first person to publish his or her findings.
In Greek, the word bromos means "stench" strong, offensive odor. Bromine lives up to the description. The odor is intense and highly irritating to the eyes and lungs. Chemists found that bromine belonged in the halogen family. They knew that it had properties similar to other halogens and placed it below fluorine and chlorine in the periodic table. Only two liquid elements exist—bromine and mercury.
At room temperature, bromine is a deep reddish-brown liquid. It evaporates easily, giving off strong fumes that irritate the throat and lungs. Bromine boils at Bromine freezes at A laboratory vessel holds the solid, liquid, and gas states of bromine.
Bromine dissolves well in organic liquids—such as ether, alcohol, and carbon tetrachloride—but only slightly in water. Organic compounds contain the element carbon. Bromine is a very reactive element. While it is less reactive than fluorine or chlorine, it is more reactive than iodine.
It reacts with many metals, sometimes very vigorously. For instance, with potassium, it reacts explosively. Bromine even combines with relatively unreactive metals, such as platinum and palladium.
Bromine is too reactive to exist as a free element in nature. Skip to main content. Nonmetallic Elements. Search for:. Halogens Properties of the Halogens Halogens fluorine, chlorine, bromine, iodine, astatine are nonmetal elements that are highly electronegative and reactive. Learning Objectives Describe the physical and chemical properties of halogens. Down the group, atom size increases. As a diatomic molecule, fluorine has the weakest bond due to repulsion between electrons of the small atoms.
Due to increased strength of Van der Waals forces down the group, the boiling points of halogens increase. Therefore, the physical state of the elements down the group changes from gaseous fluorine to solid iodine.
Due to their high effective nuclear charge, halogens are highly electronegative. Therefore, they are highly reactive and can gain an electron through reaction with other elements.
Halogens can be harmful or lethal to biological organisms in sufficient quantities. Key Terms electronegativity : The tendency of an atom to attract electrons to itself. They share similar chemical properties. Halogen Compounds Halogens are highly reactive and can form hydrogen halides, metal halides, organic halides, interhalogens, and polyhalogenated compounds.
Learning Objectives Discuss halogen compounds and their properties. Key Takeaways Key Points Hydrogen halides are binary compounds of halogens with hydrogen. They are strong hydrohalic acids when dissolved in water, with the exception of HF.
All of these acids are dangerous; some are widely used in chemical manufacturing plants. Metal halides are compounds of halogens and metals. They include highly ionic compounds, monomeric covalent compounds, and polymeric covalent compounds. Metal halides can be obtained through direct combination or through neutralization of a basic metal salt with a hydrohalic acid.
Interhalogen compounds are formed when halogens react with each other. Some resemble the pure halogens in some respects, but mostly their properties and behaviors are intermediates of those of the two parent halogens. Halogenated compounds, or organic halides, are organic compounds that contain halogen atoms. In the human body, some halogens perform multiple regulatory functions, while others are not essential.
Organohalogens are synthesized through the nucleophilic abstraction reaction. Compounds substituted with multiple halogens are known as polyhalogenated compounds. Many of them are very toxic and bioaccumulate in humans, but they have many potential applications. Key Terms interhalogen : A binary compound of two different halogens. Learning Objectives Discuss the uses of various halogens.
Key Takeaways Key Points Fluoride can be found in many everyday products, including toothpaste, vitamin supplements, baby formulas, and even public water.
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