Halogens are a group of non-metallic elements in the periodic table, including fluorine, chlorine, bromine, iodine, astatine, etc. These elements have many similar chemical properties but also some unique properties.
Reaction of halogen elements with hydrogen.
From fluorine to iodine, the intensity of their elemental and hydrogen reactions gradually decreases, and the stability of the hydrides produced gradually decreases.
Halogens are reactive non-metallic elements, and the number of electrons in the outermost shell of their atoms is 7, and it is very easy to obtain one electron to achieve a stable electron configuration. As a result, halogens generally exhibit strong oxidizing properties, have high electronegativity, and are one of the most electronegative elements. The oxidation state of halogens is -1 and they are all stable except for astatine. When halogens react with metals, the metals are oxidized and halogens are reduced to halide ions. Halogens form acids and hydrohalic acids in aqueous solutions, which are due to the reaction of halogens with water to form corresponding hydrohalic acids. Hydrohalic acid is a strong acid. In addition, halogens can also form a variety of oxyacids and oxygenates, such as chloric acid, bromoic acid, iodic acid, etc. Halogens also have a wide range of applications in organic chemistry. Since halogen atoms can increase the reactivity of organic matter, they are more likely to react with other molecules or groups. Therefore, in organic synthesis, halogens are usually introduced into organic molecules for subsequent reactions. In addition, halogens can also be used in the preparation of many important compounds, such as vinyl chloride, ethyl bromide, methyl iodide, etc. Halogens also exhibit some unique properties. For example, fluorine is the most chemically reactive halogen, and it can react with almost all elements. Chlorine is a yellowish-green gas that dissolves in water and can form important compounds such as hydrochloric acid and hypochlorous acid. Bromine is a reddish-brown liquid that is highly volatile and can react with many substances. Iodine is a purple-black solid with a high vapor pressure that can react with many substances to form iodide. Halogens are a group of chemically important elements that have a wide range of applications in chemical, industrial, and life sciences. Through the study and application of the chemical properties of halogens, we can better use these elements to improve human life and promote the development of science and technology.