The element Bromine (Br), atomic number 35, is not a metal. Confusion often arises because it is one of only two elements on the periodic table that exists as a liquid at standard room temperature, the other being mercury. Elemental bromine is a dense, reddish-brown fluid that readily vaporizes into a similarly colored gas. Its properties place it firmly in the category of nonmetals, a classification determined by its atomic structure and chemical behavior.
Bromine is a Nonmetal and a Halogen
Bromine is chemically classified as a nonmetal, a group of elements that lack the luster, malleability, and electrical conductivity characteristic of metals. Nonmetals are located on the right side of the periodic table, separated from metals by metalloids. The fundamental difference lies in their electron affinity, as nonmetals tend to gain electrons to achieve a stable configuration.
This element belongs to Group 17, known as the Halogen family, which includes fluorine, chlorine, iodine, and astatine. Bromine’s chemical behavior is driven by its strong tendency to acquire a single electron. This high reactivity means elemental bromine (Br₂) is rarely found freely in nature, occurring instead as bromide salts in seawater and brines.
Distinctive Physical and Chemical Properties
Bromine’s physical state is defining, existing as a liquid with a melting point of -7.2°C and a boiling point of 58.8°C. Since room temperature falls between these points, it remains liquid, unlike the other halogens which are gases or a solid. This liquid state results from intermediate intermolecular forces between its diatomic molecules (Br₂).
Bromine exhibits the poor conductivity of both heat and electricity typical of nonmetals. It is a volatile, dense, reddish-brown liquid that gives off a pungent, amber-colored vapor. Furthermore, elemental bromine is highly corrosive and toxic, readily combining with most elements to form various bromide compounds.
Bromine’s Placement on the Periodic Table
Bromine’s position on the periodic table, specifically in Period 4 and Group 17, is the reason for its non-metallic classification. Its Group 17 placement indicates that a bromine atom has seven valence electrons in its outermost shell. This means the atom is just one electron short of the stable, full octet found in noble gases.
This electron deficit dictates the element’s chemistry, driving the strong oxidizing behavior where the atom seeks to gain that single electron. The resulting negative ion, bromide (Br⁻), achieves stability by having a full outer shell. This preference for gaining, rather than losing, electrons is the definitive characteristic that classifies bromine as a nonmetal.