卤素是卤族元素的简称,是周期系ⅦA族元素.该族元素包括氟(F)、氯(Cl)、溴(Br)、碘(I)、砹(At).它们在自然界都以典型的盐类存在,是成盐元素.卤族元素的单质都是双原子分子,它们的物理性质的改变都是很有规律的,随着分子量的增大,卤素分子间的色散力逐渐增强,颜色变深,它们的熔点、沸点、密度、原子体积也依次递增.卤素都有氧化性,氟单质的氧化性最强.卤族元素和金属元素构成大量无机盐,此外,在有 Halogen is an abbreviation of a halogen element and is a Group VIIA element of the periodic system, which includes fluorine (F), chlorine (Cl), bromine (Br), iodine (I), azulene (At) Of salt is salt forming element.Halogen elements are diatomic elements, their physical properties change is very regular, with the increase of molecular weight, the dispersion of halogen molecules gradually increased, The color becomes darker, and their melting points, boiling points, densities, and atomic volumes increase in turn. Halides are oxidized and fluorine is the most oxidizable element. Halogen elements and metal elements constitute a large amount of inorganic salts. In addition,