The 35th element of the periodic table is bromine. The element of group-17 is bromine and its symbol is ‘Br’. Bromine is a halogen element and forms bonds through its valence electrons. This article discusses in detail how to easily calculate the number of valence electrons in bromine. Hopefully, after reading this article you will know in detail about this.
How many protons and electrons does bromine have?
The nucleus is located in the center of the atom. Protons and neutrons are located in the nucleus. The atomic number of bromine is 35. The atomic number is the number of protons. That is, the number of protons in bromine is thirty-five. Electrons equal to protons are located in a circular shell outside the nucleus. That is, a bromine atom has a total of thirty-five electrons.
What are the valence electrons of bromine?
Bromine is a non-metallic element. The valence electrons are the total number of electrons in the last orbit(shell). The total number of electrons in the last shell after the electron configuration of bromine is called the valence electrons of bromine. The valence electrons determine the properties of the element and participate in the formation of bonds.
How do you calculate the number of valence electrons in a bromine atom?
The valence electrons have to be determined by following a few steps. The electron configuration is one of them. It is not possible to determine the valence electrons without electron configuration. Knowing the electron configuration in the right way, it is very easy to determine the valence electrons of all the elements.
However, valence electrons can be easily identified by arranging electrons according to the Bohr principle. Now we will learn how to determine the valence electron of bromine.
Step-1: Determining the total number of electrons in bromine
1st we need to know the total number of electrons in the bromine atom. To know the number of electrons, you need to know the number of protons in bromine. And to know the number of protons, you need to know the atomic number of the bromine element.
To know the atomic number we need to take the help of a periodic table. It is necessary to know the atomic number of bromine elements from the periodic table. The atomic number is the number of protons. And electrons equal to protons are located outside the nucleus.
That is, we can finally say that there are electrons equal to the atomic number in the bromine atom. From the periodic table, we see that the atomic number of bromine is 35. That is, the bromine atom has a total of thirty-five electrons.
Step-2: Need to do electron configuration of bromine
Step-2 is very important. In this step, the electrons of bromine have to be arranged. We know that bromine atoms have a total of thirty-five electrons. The electron configuration of the bromine shows that there are two electrons in the K shell, eight in the L shell, eighteen in the M shell, and seven in the N shell.
That is, the first shell of bromine has two electrons, the second shell has eight electrons, the 3rd shell has eighteen electrons and the 4th shell has seven electrons. The number of electrons per shell of bromine is 2, 8, 18, 7.
Step-3: Determine the valence shell and calculate the total electrons
The third step is to diagnose the valence shell. The last shell after the electron configuration is called the valence shell. The total number of electrons in a valence shell is called valence electrons. The electron configuration shows that the last shell of bromine has seven electrons. Therefore, the valence electrons of bromine are seven.
How many valence electrons does bromide ion(Br–) have?
The elements that have 5, 6, or 7 electrons in the last shell receive the electrons in the last shell during bond formation. The elements that receive electrons and form bonds are called anions. During the formation of a bond, the last shell of bromine receives an electron and turns into a bromide ion(Br–). That is, bromine is an anion element.
Br + e– → Br–
The electron configuration of bromide ion is 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6. The electron configuration shows that the bromide ion(Br–) has acquired the electron configuration of krypton. Since the last shell of the bromine ion has eight electrons, the valence electrons of the bromine ion(Br–) are eight.
What is the valency of bromine?
The ability of one atom of an element to join another atom during the formation of a molecule is called valency(valence). The number of unpaired electrons in the last orbit of an element is the valency of that element. The correct electron configuration of bromine(Br) in the ground state will be 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4px2 4py2 4pz1.
This electron configuration shows that the last shell of a bromine atom has an unpaired electron. So in this case, the valency of bromine is 1. The valency of the element is determined by electron configuration in the excited state. When the bromine atom is excited, then the bromine atom absorbs energy. As a result, an electron in the 4py sub-orbital jumps to the 4dxy1 orbital.
Therefore, the electron configuration of bromine(Br*) in excited state will be 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4px2 4py1 4pz1 4dxy1. Here, bromine has three unpaired electrons. So in this case, the valency of bromine is 3. Bromine atom exhibit -1, +1, +3, +5 oxidation states. The oxidation state of the element changes depending on the bond formation.