Bromine has an atomic number of 35, which means it has 35 protons and 35 electrons. The two stable isotopes of bromine are Br-79 and Br-81, which contain 44 and 46 neutrons respectively. Bromine is a member of the halogen group and is designated with the chemical symbol "Br."
Bromine was discovered in 1826 and first manufactured for commercial purposes in 1860. The name comes from the Greek word for "stench" because bromine is a reddish-brown liquid that becomes a foul-smelling vapor at room temperature. It is a toxic element that is corrosive to the skin and irritating to the eyes and throat. Bromine is used to make solvents, fire retardant compounds and purification systems for swimming pools.