Bromine (Br, atomic number 35) is a chemical element. The definitive answer to its classification is that Bromine is a nonmetal. It is the only nonmetal, and one of only two elements, that exists as a liquid at standard room temperature and pressure.
Bromine’s Classification as a Nonmetal
Bromine is classified as a nonmetal based on its distinct physical and chemical properties, which contrast sharply with those of metals. It is a poor conductor of both heat and electricity. Bromine lacks metallic luster, and solid Bromine (which forms below -7.2°C) is brittle rather than malleable. It is a volatile, heavy, reddish-brown liquid that easily vaporizes into a similarly colored gas. The element’s strong, pungent odor (Greek bromos means “stench”) is a key physical identifier.
Chemically, Bromine has high electronegativity (2.96 on the Pauling scale). It strongly seeks to gain a single electron to achieve a stable outer shell configuration. When reacting with metals, it readily forms the negatively charged bromide ion (Br⁻).
Bromine’s Placement in the Halogen Family
Bromine’s chemical identity is influenced by its location in Group 17, placing it within the Halogen family. It is situated in Period 4, directly below Chlorine and above Iodine. All elements in Group 17 possess seven valence electrons in their outermost shell.
This configuration explains its high chemical reactivity. Elemental Bromine is so reactive that it is never found alone in nature, existing instead as a diatomic molecule (Br₂) or as bromide salts. Following the general trends of the periodic table, Bromine’s reactivity is intermediate between its neighbors in the group. It is a less powerful oxidizing agent than Chlorine but is more reactive and a stronger oxidizing agent than Iodine.
Common Applications and Safety Considerations
Bromine and its compounds are utilized across diverse industries. One widespread application is in the manufacturing of flame retardants, where brominated compounds are added to electronics, plastics, and textiles to inhibit fire. Bromine is also commonly used as a disinfectant and sanitizer, particularly in swimming pools and hot tubs, often serving as an alternative to chlorine. Bromine compounds are also used in the synthesis of various pharmaceuticals and agricultural chemicals. Silver bromide (AgBr) is an essential component in traditional photographic film and paper.
Handling elemental Bromine requires strict safety protocols because it is a corrosive liquid and its vapor is highly toxic. The reddish-brown vapor is acutely irritating to the eyes, skin, and respiratory tract, and inhalation can lead to severe issues like pulmonary edema. Direct contact with liquid Bromine on the skin can cause painful, slow-healing burns and sores. Proper ventilation and the use of specialized personal protective equipment are mandatory when working with this element.