Halogen (Cheat Sheet)

Halogen Halogens, consisting of fluorine, chlorine, bromine and iodine, were never discovered in a free state in nature because of its very high level of reactivity. Therefore, halogens are only found as anions in the form of salts and minerals. Haloge are non-metallic elements which exist in molecular form diatomic. Halogens have a valence electron configuration of ns2 np5. 1. Physical Properties From table above, it appears that the boiling point and melting point increase along with increase in atomic number. This is because the facts show that Larger molecules have Van der forces of attraction Waals that are larger than those of larger molecules small. Except for the noble gases, halogens have the highest ionization energy and electronegativity of any group of elements. From the elements group VII A, fluorine is the one that binds its electrons most tightly, and the weakest iodine. This tendency could be related to size halogen atoms. 2. Chemical Properties There is a regular decrease in the chemical activity of fluorine to iodine, as indicated by the trend in strength oxidize it. The two-atom fluorine molecule (diatom) F2 is a stronger oxidizing agent than any other element in normal condition. There is a regular decrease in the chemical activity of fluorine to iodine, as indicated by the trend in strength oxidize it. The two-atom fluorine molecule (diatom) F2 is a stronger oxidizing agent than any other element in normal condition. The four halogen elements are all very stimulating against the nose and throat. Bromine, a dark red liquid, on Room temperature has a high vapor pressure. Liquid bromine is one of the most dangerous chemical reagents due to the effects of its vapors to the eyes and nasal passages. Chlorine and fluorine should be used only in acid rooms and in rooms with air exchange (ventilation) the good one. Several puffs of chlorine at 1,000 ppm with our breath will turn off. All halogens should be stored away from contact with substances which can be oxidized. The halogen reactions are as follows. a. Halogen Reactions with Metals Halogens react with all metals in the periodic system of elements to form metal halides. If it reacts with alkali and alkaline earth metals, the result (metal halide) can be easily predicted, whereas if it reacts with transition metals, the product (metal halide) that is formed depends on the reaction conditions and the amount of reactant. Reaction: 2 M + n X2 2 MXn , where: M = metal X = F, Cl, Br, I Unlike metal elements, as you go down, halogens become less reactive because their electron affinity decreases, or in other words others F2 > Cl2 > Br2 > I2 . b. Reaction of Halogens with Hydrogen Halogens react with hydrogen gas to form hydrogen halides (HX). Hydrogen halides are valuable because they are acidic when dissolved in water. Except for hydrogen fluoride, all other hydrogen halides are strong acids when placed in solution Reaction: H2 (g) + X2 2 HX(g), where X = F, Cl, Br, I c. Halogen Reactions with Other Halogens Halogens have diatomic molecules, so it is not surprising that reactions can occur between elements in the halogen group. This reaction between halogens can be compared to a redox process, where the more reactive element is the oxidizer, while the less reactive element is the reducing agent. Reaction: X2 + Y2 2 XY, with X, Y = F, Cl, Br, I