Bromine valence electrons

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Bromine valence electrons
Bromine valence electrons | Image: Learnool

Bromine has 7 valence electrons.


We can write the valence electrons of bromine using two different methods:

#1 Using periodic table
#2 Using electron configuration

Let’s break down each method in detail.

Using periodic table

Periodic table | Image: Learnool

Get the periodic table having the chemical elements marked on it as mentioned above.

Now mark the location of bromine on the periodic table.

Bromine location marked on periodic table | Image: Learnool

Next, mark the group number of bromine on the periodic table.

Bromine group number marked on periodic table | Image: Learnool

The valence electrons of each main-group element can be determined by the column in which it is located.

(i.e., all group 1 elements have 1 valence electron, all group 2 elements have 2 valence electrons, skip the transition metals… then, all group 13 elements have 3 valence electrons, all group 14 elements have 4 valence electrons, and so on up to group 18 elements)

Since bromine is in group 17, it has 7 valence electrons.

Using electron configuration

  • First, write electron configuration of bromine

The electron configuration of bromine is [Ar] 4s2 3d10 4p5.

  • Second, find highest energy level in electron configuration
Green colored number represent highest energy level | Image: Learnool

In the above electron configuration, the highest energy level (4) is marked with green color.

  • Finally, count electrons of that energy level
Number circled with green color represent electrons | Image: Learnool

The 4th energy level contains 4s and 4p subshells. There are 2 electrons in the 4s subshell and 5 electrons in the 4p subshell. So bromine has a total of 2 + 5 = 7 valence electrons.

Next: Krypton valence electrons


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