In elemental form, halogens must be kept in inert containers like sealed glass flasks. They’re also corrosive and poisonous, making them ideal disinfectants…but also potential chemical weapons. Meanwhile, tennessine is a highly transitory synthetic element with just a few milliseconds of half-life.Īll halogens are highly reactive because of their electron configuration. Astatine has never been assembled at macroscopic scale but is probably semi metallic or metallic. For example, fluorine is a gas, bromine is liquid, and iodine is a crystalline solid. Refer to this pattern in the periodic table to compare the trends in the ionisation energy, electron affinity, atomic radius, and the metallic/non-metallic characteristics of the elements:Īt room temperature, halogens vary in state of matter. However, some have potential practical applications. They’re industrially formed as waste products that are very toxic to humans and other animals.

Polyhalogenated compounds : These are synthetic compounds with multiple halogen constituents.

Similarly, iodine is needed in very small amounts to synthesise thyroid hormones. In humans, for instance, chloride ions are necessary for brain functionality. Some also have essential roles in biological functions.

Organic halides: Many of these compounds are synthetic, like plastic polymers, but a few are also naturally occurring.

Some examples include bromine fluoride (BrF), iodine monochloride (ICl), and chlorine monofluoride (ClF).

Interhalogen compounds: Halogens can also react with other halogens to form compounds.

Generally, halogens can react directly with metals, but they can also react via their acidic compounds. Halogens can also form polymeric covalent compounds with metals like palladium chloride. The bonds can be highly ionic, such as those formed with alkali metals.

Metal halides : These are compounds formed with many types of metals, including alkali metals and radioactive metals such as uranium (uranium hexafluoride).

These are essentially salts but, when dissolved in water, they become acids, namely hydrofluoric acid, hydrochloric acid, and hydrobromic acid. Examples of these are hydrogen fluoride, hydrogen chloride, and hydrogen bromide. Hydrogen halides: All compounds formed with the reaction between hydrogen and a halogen.Their products can be categorised in the following ways: Various chemicals can be formed by the reaction of halogens with other elements and compounds. With the presence of a small amount of water, fluorine can react with its glass container, forming silicon tetrafluoride, or SiF 4. It can even react with materials that are considered inert, like glass. In fact, it can be argued that it’s the most reactive naturally-occurring element that we know of. However, as the atomic radius increases, the stability of the diatomic bonds decreases.įluorine is the most reactive element of all halogens. As elements, halogens exist as diatomic molecules (molecules made up of two atoms). Therefore, higher electronegativity means stronger reactivity. All halogens are highly electronegative due to the high effective nuclear charge of the elements.Įlectronegativity measures the ability or tendency of an atom to attract electrons in either shared covalent bonds or in ionic bonds.

Additionally, they all have an ‘ s’ (spherical shape) and a ‘ p’ (dumbbell shape) orbital in the outermost shell. Halogens have seven valence electrons in their outermost energy level, which can be denoted by ns 2np 5. This is mainly because of their atomic structures and electron configuration. Just like other groups in the periodic table of elements, the six elements in column 17 have similar chemical and physical properties. What Are the General Properties of Halogens? What Are the Elements in the Halogen Group?.What Are the General Properties of Halogens?.

Halogen periodic table