What is Bromine Definition Electronic Configuration Oxidation States Reactions and Uses
When you think about Bromine, you may imagine something reddish-brown. Gases containing bromine atoms have not such pleasing colours, have a foul smell, and they can irritate your nose and skin. The name bromine has derived from the Greek word ‘Bromos,’ which means something that smells bad. Its symbol is ‘Br’, and the bromine atomic number is 35. It’s a member of the halogen family of elements; fluorine, chlorine, and iodine are its companions. The Br element can cause serious health problems to humans. Nonetheless, it still is highly useful in our lives. Balard found this element in 1826. One of the fascinating things about Bromine is that it’s the only non-metallic element which is a liquid at room temperature. You can learn about properties, uses, and facts about Bromine further in this article.
What is Bromine?
Bromine is a chemical element with a fuming brown-red liquid. The noxious liquid is a member of the halogen family of the periodic table. It is the third-biggest halogen with an exceptional vapour pressure at room temperature. And it’s the only non-metallic element that stays in a liquid state at room temperature.
Physical Properties of Bromine
Before we move onto some unique properties of Br element, below are some fundamental physical properties.
Bromine belongs to the group – 17, period – 4, and block – p.
Bromine electron configuration is [Ar] 3d¹⁰ 4s² 4p⁵, and its atomic number is 35.
Its melting point is −7.2°C, 19°F, 266 K and boiling point is 58.8°C, 137.8°F, 332 K.
The relative atomic weight is 79.904, and it has a density of (g cm-3) 3.1028.
The appearance of an element is reddish-brown, and it has metallic lustre in solid-state.
Bromine has 29 known isotopes; it ranges from Br-69 to Br-97. And there are two stable isotopes Br-79 and Br-81.
Chemical Properties of Bromine
Bromine has significantly high electron affinity, which is equivalent to chlorine. However, the oxidizing power of bromide is relatively low as bromide ion has weaker hydration than chloride ion.
Bromine gels violently with alkali metals and with aluminium, arsenic, phosphorus and antimony. But it combines less violently with other particular metals.
Bromine tends to displace hydrogen from saturated hydrocarbons and adds it to unsaturated hydrocarbons, but not as seamlessly as chlorine does.
Bromine has high first ionization energy and compounds that contain Bromine get stabilized by appropriate ligands, primarily oxygen and fluorine. Compounds having oxidation numbers +1, +3, +4, +5, and +7 all have covalent bonds.
Uses of Bromine
Right from the discovery of Bromine, its compounds have a majority of applications across different industries. Below are some important purposes that bromine servers.
Water Purification: Purifying or disinfecting the water is a major use of Bromine. It serves as an alternative to chlorine. Brominated compounds get used to treating water in swimming pools and hot tubs. It also helps prevent algae and bacterial growth in industrial processes.
Pesticides: As you know that Bromine is poisonous to the human body, it also has a major application in pesticides. It can efficiently control insect infestations.
Healthcare: Brominated substances are an essential ingredient of over-the-counter and prescription drugs, which includes analgesics, antihistamines, and sedatives. Some drugs have been successful in treating pneumonia and cocaine addiction.
Photography: Many liquids get used to developing perfect photographs. Bromine compounds get used to making a vital light-sensitive part of a photographic emulsion. A picture wouldn’t be able to capture adequate light if not for bromine compounds. They also help with photo development.
Plastics: You must know that all plastics are not the same; you can say so by looking at your toys and other devices in your home. There is a unique plastic which is flame resistant. And Bromine gets used to manufacturing those flame-resistant products.
Few Facts About Bromine
Elemental Bromine is poisonous, and it causes corrosion burns upon contact with the skin. Also, inhalation in low concentration lead to irritation and inhaling in higher concentration can cause death too.
Bromine ranks 64th in the list of most abundant elements found in earth’s crust, having an abundance of 2.4 mg/kg.
Elemental Bromine has a reddish-brown colour and a liquid state at room temperature. Mercury is the only other element that has a liquid state at room temperature.
FAQs on Bromine Element Structure Properties and Chemical Behavior
1. What is bromine?
Bromine is a chemical element with the symbol Br and atomic number 35 that belongs to the halogen group. It is a red-brown liquid at room temperature and is the only nonmetal that exists as a liquid under standard conditions. Key facts about bromine include:
- Group: 17 (halogens)
- Period: 4
- Atomic mass: approximately 79.9 u
- Molecular form: Br2(l)
2. Why is bromine a liquid at room temperature?
Bromine is a liquid at room temperature because its intermolecular London dispersion forces are strong enough to give it a melting point below room temperature and a boiling point above it. Compared to other halogens:
- F2 and Cl2 are gases (weaker intermolecular forces).
- Br2 is a liquid.
- I2 is a solid (stronger intermolecular forces).
3. What is the electron configuration of bromine?
The electron configuration of bromine (atomic number 35) is [Ar] 3d10 4s2 4p5. This means:
- It has 35 electrons.
- The outer (valence) shell configuration is 4s2 4p5.
- It has 7 valence electrons, typical of halogens.
4. What are the common oxidation states of bromine?
The most common oxidation states of bromine are −1, +1, +3, +5, and +7. These vary depending on the compound:
- −1 in bromides such as NaBr.
- +1 in hypobromites like NaBrO.
- +5 in bromates such as KBrO3.
- +7 in perbromates like KBrO4.
5. How does bromine react with metals?
Bromine reacts with metals to form metal bromides in a synthesis (combination) reaction. For example:
- 2Na(s) + Br2(l) → 2NaBr(s)
- Sodium is oxidized (loses electrons).
- Bromine is reduced to Br−.
6. How does bromine react with alkenes?
Bromine reacts with alkenes by an addition reaction across the carbon–carbon double bond, forming a dibromo compound. For example:
- C2H4(g) + Br2(l) → C2H4Br2(l)
- Breaks the C=C double bond.
- Adds one Br atom to each carbon.
- Is used as a test for unsaturation because bromine’s reddish-brown color disappears.
7. What is the test for bromine gas?
The test for bromine gas is its characteristic reddish-brown color and its ability to bleach moist litmus paper. Key observations include:
- Reddish-brown fumes.
- Turns moist blue litmus paper red (acidic effect).
- Then bleaches it due to its oxidizing properties.
8. What is the difference between bromine and chlorine?
The main difference between bromine and chlorine is that bromine is a liquid at room temperature, while chlorine is a gas. Key comparisons:
- Chlorine (Cl2): greenish-yellow gas, more reactive.
- Bromine (Br2): red-brown liquid, less reactive than chlorine.
- Reactivity decreases down Group 17: Cl > Br.
- Cl2(g) + 2KBr(aq) → 2KCl(aq) + Br2(l)
9. What are the uses of bromine?
Bromine is used in flame retardants, water treatment, and the production of organic and inorganic bromine compounds. Major applications include:
- Flame retardants in plastics and textiles.
- Water disinfection in swimming pools and spas.
- Manufacture of silver bromide (AgBr) for photography.
- Production of pharmaceuticals and agrochemicals.
10. Is bromine toxic or dangerous?
Yes, bromine is highly toxic and corrosive, especially in its liquid and gaseous forms. Health hazards include:
- Severe skin and eye burns.
- Respiratory irritation from inhaling Br2 vapors.
- Harmful effects if swallowed.
