How Many Valence Electrons Does Chlorine (Cl) Have?

The 17th element of the periodic table is chlorine and it is also an element of group-17. Its symbol is ‘Cl’. 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 chlorine is called the valence electrons of chlorine. The last shell of chlorine has seven electrons. Therefore, the valence electrons of chlorine are seven.

Chlorine is a non-metallic element and also a halogen element. The valence electrons determine the element’s properties and participate in forming bonds. Chlorine forms bonds through its valence electrons.

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How do you calculate the number of valence electrons in a chlorine 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 electron 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 chlorine.

Step-1: Determining the total number of electrons in chlorine

1st we need to know the total number of electrons in the chlorine atom. To know the number of electrons, you need to know the number of protons in chlorine.

To know the number of protons, you need to know the atomic number of the chlorine 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 chlorine elements from the periodic table. The atomic number is the number of protons. 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 chlorine atom. From the periodic table, we see that the atomic number of chlorine is 17. That is, the chlorine atom has a total of seventeen electrons.

Step-2: Need to do electron configuration of chlorine

Step 2 is very important. In this step, the electrons of chlorine have to be arranged. The electron configuration of chlorine shows that there are two electrons in the K shell, eight in the L shell, and seven in the M shell.

That is, the first shell of chlorine has two electrons, the second shell has eight electrons and the 3rd shell has seven electrons.

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 chlorine has seven electrons. Therefore, the valence electrons of chlorine are seven.

What is the valency of chlorine?

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 chlorine(Cl) in the ground state will be 1s² 2s² 2p⁶ 3s² 3p_x² 3p_y² 3p_z¹.

This electron configuration shows that the last shell of the chlorine atom has an unpaired electron(3p_z¹). So the valency of chlorine is 1.

The oxidation states of chlorine change depending on the excitation. Oxidation states of chlorine are −1, +1, +2, +3, +4, +5, +6, +7.

How many valence electrons does chloride ion(Cl^–) 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 chlorine receives an electron and turns into a chloride ion(Cl^–). That is, chlorine is an anion element.

Cl + e^– → Cl^–

The electron configuration of chloride ion(Cl^–) is 1s² 2s² 2p⁶ 3s² 3p⁶.

The electron configuration of chlorine ions shows that chloride ions have three shells and the 3rd shell has eight electrons.

This electron configuration shows that the chloride ion has acquired the electron configuration of argon.

That is, in this case, the valency of chlorine ions is -1. Since the last shell of the chloride ion has eight electrons, the valence electrons of the chloride ion(Cl^–) are eight.

Compound formation of chlorine

Chlorine participates in the formation of bonds through its valence electron. These valence electrons participate in the formation of bonds with atoms of other elements.

The electron configuration of sodium shows that the valence electrons of sodium are one. The sodium atom donates its valence electrons to the chlorine atom and the chlorine atom receives that electron.

As a result, chlorine acquires the electron configuration of argon and the sodium atom acquires the electron configuration of neon.

Chlorine and sodium atoms form sodium chloride(NaCl) bonds through electron exchange. Sodium chloride(NaCl) is ionic bonding.

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