Bromine
Definition and meaning of Bromine in chemistry.
![Bromine element card: symbol Br, atomic number 35, atomic mass 79.904, electron configuration [Ar] 3d¹⁰ 4s² 4p⁵, oxidation states +5 +3 +1 -1, Halogen, group 17, period 4, liquid at room temperature.](/assets/images/terms/bromine-chemical-element.webp)
Bromine is a halogen element with the symbol Br and atomic number 35. This element is the only nonmetal on the periodic table that is liquid at room temperature. It is the third lightest halogen and is highly reactive.
In more detail
Bromine sits in group 17 on the periodic table, between chlorine and iodine. Its reactivity falls right between these two elements because of its size and electron structure. The dark red-brown liquid releases toxic fumes that turn into a heavy gas very easily.
This gas sinks because it is much denser than normal air. You will not find pure elemental bromine in nature. It exists naturally as colorless salt compounds in rocks and water.
These salts look and act a lot like normal kitchen table salt. Bromine has high electronegativity, which means it pulls shared electrons toward its nucleus very strongly. This property makes the element bond quickly with metals to form ionic compounds called bromides.
Mining companies extract bromine from deep pools of salty water called brine. They also pump huge amounts of it from the very salty Dead Sea. Many students think bromine is a metal because it is heavy and dense. However, it lacks metallic luster and does not conduct electricity.
Key facts
| Field | General Chemistry |
|---|---|
| Symbol | Br |
| Atomic number | 35 |
| Atomic mass | 79.904 u |
| Category | Halogen |
| State at room temperature | Liquid |
| Boiling point | 58.8 degrees Celsius |
Factories used to put organic bromine compounds into plastics and fabrics to prevent fires. These substances act as flame retardants by stopping the chemical reactions that keep a fire burning. They saved many electronic devices and clothes from burning. However, scientists found that these chemicals build up in the environment and harm human health. Because of this danger, governments have banned many bromine flame retardants in recent years. Today, researchers look for safer options that still protect materials from fire without causing long-term harm.
Frequently asked questions
Why is liquid bromine dangerous in a lab?
Liquid bromine eats through skin quickly and causes severe chemical burns. Its red-brown fumes are very toxic. Breathing this heavy gas can permanently damage a person's throat and lungs.
Does pure bromine have a smell?
Yes, it has a sharp and choking smell that is very harsh. The odor is a lot like strong chlorine gas. Its name even comes from an old Greek word meaning stench.
Why does bromine form ions with a negative one charge?
Bromine has seven valence electrons in its outer shell. It needs just one more electron to reach a stable state. Therefore, it easily gains one electron to form a Br- ion.
Related terms
Sources & references
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