Group 17- Halogens group PDF

Inorganic Chemistry II (Chem 3120) Dr/ Amal Nassar Chemistry Department, College of Sciences and Humanities, Prince Sattam bin Abdulaziz University. 1  Group 7A(17): Halogens group Mr R. Tucker (PP02_2005) Group 7A(17...

Inorganic Chemistry II (Chem 3120) Dr/ Amal Nassar Chemistry Department, College of Sciences and Humanities, Prince Sattam bin Abdulaziz University. 1  Group 7A(17): Halogens group Mr R. Tucker (PP02_2005) Group 7A(17): The Halogens Six chemical elements in Group 16 (VIIA) of the periodic classification namely, fluorine (F), chlorine (Cl), bromine (Br), iodine (I) are nonmetals astatine (At), and tennessine (Ts). are metalloids  Group 7A(17): Halogens group Properties All the elements in Group 17 are nonmetals except for astatine, which is a radioactive metalloid. These elements are called halogens, which means “salt-former.” All the halogens form salts with sodium and with the other alkali metals. exist as separate diatomic molecules all have the electronic configuration ns2 np5 Each atom is 1 electron short of a noble gas electron structure, By sharing electrons in a covalent bond full outer electron shells are achieved so halogens form ions with a -1 charge  Group 7A(17): Halogens group Halogens are all coloured elements Element Colour Physical Melting Boiling State Point (oC) Point (oC) Fluorine Yellow GAS -220 -188 Chlorine Green GAS -101 -35 Bromine Orange- LIQUID -7 59 brown Iodine Purple SOLID +114 184 Fluorine As you go down the group: Chlorine The halogens become darker in colour and denser The melting and boiling point increases Bromine The radius of the atom increases because there are Iodine more electron shells The elements become LESS reactive  Group 7A(17): Halogens group Halogen vapours Bromine and iodine are not gaseous, but have low boiling points. This means that they produce vapour at relatively low temperature. They are volatile. When iodine is heated gently, it changes directly from a solid to Bromine produces some a gas without first becoming a orange-brown vapour, liquid. seen here above, the vapour diffuses up the This is called sublimation. gas jar.  Group 7A(17): Halogens group Occurrence: All the halogens occur in seawater as halide ions. Fluoride is a pale-yellow gas occurs in minerals such as CaF2. Chloride is a greenish gas occurs in the Great Salt Lake and the Dead Sea, Part of the chlorine in your body is present as hydrochloric acid, which is a component of stomach acid. Bromine is a dark red liquid occur in the Dead Sea and underground salt-water. Iodine is a black solid and are found in small quantities in Chile saltpeter, underground brines, and sea kelp. Iodine is essential to the function of the thyroid gland.  Group 7A(17): Halogens group uses Fluoride fluoride can be found in many everyday products, including toothpaste, vitamin supplements, and even public water. Many dental products contain fluoride in order to prevent tooth decay, but overconsumption of fluoride can be fatal. Chlorine Chlorine accounts for about 0.15 percent of human body weight. Chlorine is used in the production of hydrochloric acid, which is secreted from the wall cells in the stomach and is used in keeping the acidic environment. Chlorine also reacts with sodium to create sodium chloride, more commonly known as table salt.  Group 7A(17): Halogens group Both chlorine and bromine are used as disinfectants for drinking water, swimming pools, fresh harms, spas, and surfaces. They kill bacteria and other harmful microorganisms through a process known as purification. Iodine Iodine plays a vital role in thyroid health. Use in treating thyroid cancer. Use in disinfecting water.  Group 7A(17): Halogens group Chemical properties displacement reactions : Halogens participate in displacement reactions with halide ions. 2KBr+ Cl2 → 2KCl +2Br With metals The halogens react with metals to produce salts 2Na(s) + Cl2(g) → 2NaCl(s) With hydrogen The halogens react with hydrogen gas to product hydrogen halides H2+ Cl2 → 2HCl  Group 7A(17): Halogens group The halogens become less reactive going down group 7. The table describes the reactions of the halogens with iron and hydrogen Halogen Reaction with iron Reaction with Hydrogen Fluorine Cold iron wool burns to produce Explodes in the cold and dark, white iron(III) fluoride forming hydrogen fluoride Chlorine Hot iron wool burns vigorously to Explodes with a flame or in produce orange-brown iron(III) sunlight, forming hydrogen chloride chloride Bromine Hot iron wool burns quickly to Vigorous reaction with burning produce red-brown iron(III) hydrogen, forming hydrogen bromide bromide Iodine Hot iron wool reacts slowly in Very slow reaction when heated iodine vapor to produce grey strongly, forming some hydrogen iron(II) iodide iodide https://www.youtube.com/watch?v=EvtyMr5EvBY  Chlorine (O2) The symbol shows a gas mask. This is because chlorine is a toxic gas and has been used as a chemical weapon. Chlorine is yellowy-green in color, as is the image.  Chlorine (Cl2) Occurrence and uses 1. Chlorine is not found uncombined in nature. Halite (sodium chloride or ‘common salt’) is the main mineral that is mined for chlorine. 2. Chlorine kills bacteria – it is a disinfectant. 3. It is used to treat drinking water and swimming pool water. 4. It is also used to make hundreds of products from paper to paints, and from textiles to insecticides. 5. chlorine used to make Polyvinyl chloride (PVC). This is a very multiple plastic used in window frames, car interiors, electrical wiring insulation, water pipes, blood bags and vinyl flooring. 6. chlorine use in organic chemistry as an oxidizing agent. 7. Chlorine gas is itself very poisonous and was used as a chemical weapon during the First World War.  Chlorine (Cl2) Laboratory Preparation of Chlorine Chlorine can be prepared by removing the hydrogen from hydrochloric acid using an oxidizing agent such as manganese dioxide MnO2 + HCl→MnCl2 + Cl2 + 2H2O  Chlorine (Cl2) Chemical Properties of chlorine A chlorine atom has 7 electrons in its outer shell The electron configuration is as follows: 1s22s22p63s23p5 The common oxidation state of chlorine are -1 (in the case of HCl and NaCl) and 0 (in the case of Cl2). The examples of other oxidation states of chlorine are shown below: Chlorine displaces the heavier, less electronegative halogens, bromine and iodine, from compounds. The displacement of bromides, for example, occurs according to the following equation: 2KBr+ Cl2 → 2KCl +2Br  Chlorine (Cl2) 1. Reaction of Chlorine with bases. Chlorine reacts with a hot solution of sodium hydroxide to give a mixture of Sodium Chloride and Sodium Chlorate. 3Cl2 + 6 NaOH →5 NaCl + NaClO + 3H2O 2. Reaction with water When chlorine reacts with water, it forms a mixture of hydrochloric acid, , and chloric acid,. Chloric acid is also known as hypochlorous acid , It is a powerful oxidizing agent that kills all sorts of bacteria and viruses, from common colds to cholera. We use this technique to disinfect water for both swimming pools and for drinking purposes. H2O + Cl2 → HCl + HClO  Chlorine (Cl2) 3. Oxidizing Reaction of Chlorine Chlorine is a strong oxidising agent. Chlorine oxidises Iron (II) Chloride FeCl2 to the salt containing Iron in the higher oxidation state Iron (III) Chloride FeCl3 2 Fe C l2+ C l2→ 2 Fe C l3 4. Halogenation of Organic compounds Halogenation is the replacement of one or more hydrogen atoms in an organic compound by a halogen (fluorine, chlorine, bromine or iodine). CH4 + Cl2 → CH3Cl + HCl 5. Reaction of chlorine with air Chlorine, Cl2, does not react with oxygen, O2, and nitrogen, N2.Chlorine react with carbon monoxide, CO, forming COCl2. Cl2(g) + CO(g) → COCl2(g)