Why does boiling point of halogens increase

PVC is used in wire insulation, pipes, and electronics. 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, Petrucci, Ralph H. Genereal Chemistry: Principles and Modern Applications. New Jersey: Pearson Education Inc, Verma, N. Kapila, and S. Comprehensive Chemistry XII. New Delhi: Laxmi Publications, F luo rine.

Na 3 AlF 6. Optical components, manufacture of HF, metallurgical flux. Fluorinating agent, reprocessing nuclear fuels. Ceramics manufacture, welding, and soldering. Fluoridating water, dental prophylaxis, insecticide. Insulating gas for high-voltage electrical equipment.

Manufacture of uranium fuel for nuclear reactors. The halogens are members of what is called Group 17 on the periodic table, which are named because they represent the seventeenth column from the left.

The halogens all exist as diatomic molecules in nature. In other words, they exist as two joined atoms of the element. Halogens react with metals to form halides and are oxidizing agents, especially fluorine, which is the most electronegative element.

Lighter halogens are more electronegative, lighter in color, and have lower melting and boiling points than heavier halogens. The forces that hold the molecules of halogens together are called Van der Waals dispersion forces. These are the forces of intermolecular attraction that must be overcome for liquid halogens to reach their boiling points. Electrons move in a random fashion around the nucleus of an atom. At any one time, there may be more electrons on one side of a molecule, creating a temporary negative charge on that side and a temporary positive charge on the other side -- an instantaneous dipole.

The temporary negative and positive poles of different molecules attract each other, and the sum of the temporary forces results in a weak intermolecular force. Atomic radii tend to get smaller as you move from left to right along the periodic table and larger as you move down the periodic table. One to one online tuition can be a great way to brush up on your Chemistry knowledge. Answered by Jyothi D.

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