Halogens are nonmetals. At room temperature, fluorine and chlorine are gases and bromine is a liquid. Iodine and astatine are solids. Halogens are very reactive, the reactivity decreases from fluorine to astatine. Halogens do not exist in the elemental form in nature.

Halogen Properties

We will look at some of the physical and chemical properties of Halogens.

Physical Properties

• The group of halogens is the only periodic table group that contains elements in all three familiar states of matter at standard temperature and pressure
• Fluorine (F) is a pale yellow gas
• Chlorine (Cl) is a greenish gas
• Bromine (Br) is a dark red liquid
• Iodine (I) is a black solid and when heated it forms a purple vapour
• Astatine (At) is a black solid
• The halogens all have a strong and often nasty smell
• The halogen elements are extremely toxic
• Poor conductors of heat and electricity
• Low melting and boiling points