How Many Valence Electrons Does Bromine Have?

Bromine is an element that is part of the halogen group, and it is known for its reddish-brown hue and strong smell. It is a non-metal and can be found in various compounds such as potassium bromide and sodium bromide. It is also used in water purification processes, agricultural chemicals, and medical treatments. But one of the most important aspects of this element is its electronic configuration, particularly the number of valence electrons it contains.

What are valence electrons?

Valence electrons are electrons that occupy the outermost shell of an atom. These electrons are responsible for the chemical properties of an element because they can participate in chemical reactions. The number of valence electrons an element has determines how likely it is to form bonds with other elements. In general, elements that have fewer than four valence electrons tend to lose them to form positively charged ions, while those with more than four valence electrons tend to gain electrons to form negatively charged ions.

How many valence electrons does Bromine have?

Bromine has 35 electrons, which are distributed across its shells in the following way: 2 electrons in the first shell, 8 electrons in the second shell, 18 electrons in the third shell, and 7 electrons in the fourth shell. Since the outermost shell contains 7 electrons, Bromine has 7 valence electrons.

The electronic configuration of Bromine

To understand the number of valence electrons Bromine has better, we need to examine its electronic configuration. The electronic configuration of an atom describes how its electrons are distributed across its shells. For Bromine, the electronic configuration is:

1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁵

Breaking down the electronic configuration, the 1s² and 2s² 2p⁶ shells are filled, and the 3s² 3p⁶ shell is half-filled. The 4s² and 3d¹⁰ shells are filled, and the 4p⁵ shell has 5 electrons, which make up the valence electrons.

The significance of Bromine’s valence electrons

The 7 valence electrons of Bromine are crucial in determining how it reacts with other elements. Since it only needs one more electron to complete its outermost shell, it is highly reactive and can easily form covalent or ionic bonds. In covalent bonding, two atoms share valence electrons to complete their outermost shells. Bromine can share a pair of valence electrons with another element such as fluorine to form a covalent bond.

In ionic bonding, one element (usually a metal) loses one or more electrons to another element (usually a non-metal) that gains the electrons. Bromine can gain an electron from another element such as sodium to form an ionic bond. Bromine can also share a pair of electrons with itself to form diatomic molecules, such as Br₂.

Applications of Bromine’s valence electrons

The reactivity of Bromine’s valence electrons makes it useful in various applications, such as water purification, agricultural chemicals, and medical treatments. For example, sodium bromide is used as a disinfectant in swimming pools because Bromine can easily form hypobromous acid when it reacts with water. This acid is a potent disinfectant that kills bacteria and viruses in the water.

In agriculture, potassium bromide is added to livestock feed to prevent them from becoming restless and nervous. It works by stabilizing the animal’s nerve cells, which are responsible for its behavior.

Bromine is also used in medical treatments, such as the treatment of epilepsy and schizophrenia. Sodium bromide and potassium bromide are anticonvulsant drugs that work by reducing the excitability of nerve cells in the brain. They achieve this by binding to certain receptors in the brain that are responsible for transmitting signals between nerve cells.


Bromine has 7 valence electrons, which make it highly reactive and able to form covalent or ionic bonds easily. These valence electrons are significant in determining the chemical properties of Bromine and its reactivity with other elements. Applications of Bromine’s valence electrons can be found in water purification, agricultural chemicals, and medical treatments. Understanding the electronic configuration of Bromine and its valence electrons is crucial in understanding its role in various industries and fields.

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