1. 35
Bromo – Bromine
Mass:79.904 u
Electron configuration: [Ar] 4s2
3d10
4p5
Melting point: 265.8 K, -7.2 °C, 19 °F
Boiling point: 332.0 K, 58.8 °C, 137.8 °F
Density: (Br2, liquid) 3.1028 g·cm−3
Discovery: antiquity.
Bromine (from Greek: βρῶμος, brómos, meaning "strong-smelling" or "stench") is a
chemical element with the symbol Br, and atomic number of 35. It is in the halogen
group (17). The element was isolated independently by two chemists, Carl Jacob
Löwig and Antoine Jerome Balard, in 1825–1826. Elemental bromine is a fuming red-
brown liquid at room temperature, corrosive and toxic, with properties between
those of chlorine and iodine. Free bromine does not occur in nature, but occurs as
colorless soluble crystalline mineral halide salts, analogous to table salt.
Bromine is rarer than about three-quarters of elements in the Earth's crust;
however, the high solubility of bromide ion has caused its accumulation in the oceans,
and commercially the element is easily extracted from brine pools, mostly in the
United States, Israel and China. About 556,000 tonnes were produced in 2007, an
amount similar to the far more abundant element magnesium.