How many valence electrons does chlorine(Cl) have?

The 17th element of the periodic table is chlorine. The element of group-17 is chlorine and its symbol is ‘Cl’. Chlorine forms bonds through its valence electrons. This article discusses in detail the valence electrons of chlorine(Cl).

How many electrons and protons does chlorine(Cl) have?

The nucleus is located in the center of the atom. Protons and neutrons are located in the nucleus. The atomic number of chlorine(Cl) is 17. The atomic number is the number of protons.

That is, the number of protons in chlorine(Cl) is seventeen. Electrons equal to protons are located in a circular shell outside the nucleus. That is, a chlorine atom has a total of seventeen electrons.

What are the valence electrons of chlorine(Cl)?

Chlorine(Cl) is a non-metallic element. Chlorine is a halogen element and its symbol is ‘Cl’. Chlorine is an element of group-17. The valence electron is the total number of electrons in the last orbit(shell).

valence electrons of chlorine
Valence electrons of chlorine

The total number of electrons in the last shell after the electron configuration of chlorine is called the valence electrons of chlorine(Cl). The valence electrons determine the properties of the element and participate in the formation of bonds.

The 17th element in the periodic table is chlorine. That is, the atom of the chlorine element has a total of seventeen electrons. The electron configuration of chlorine shows that the last shell(orbit) of chlorine has a total of seven electrons.

That is, we can easily say that chlorine has seven valence electrons. There is an article on this site detailing the electron configuration of chlorine(Cl), you can read it if you want.

How to determine the valence electron of chlorine(Cl)?

Now we will know how to easily determine the valence electron of chlorine(Cl). The valence electron has 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. There is an article published on this site detailing the electron configuration, you can read it if you want. However, this article briefly discusses electron configuration.

Scientist Niels Bohr was the first to give an idea of the atom’s orbit. He provided a model of the atom in 1913. The complete idea of the orbit is given there. The electrons of the atom revolve around the nucleus in a certain circular path. These circular paths are called orbit( shell). These orbits(shell) are expressed by n. [ n = 1,2 3 4 . . .]

K is the name of the first orbit(shell), L is the second, M is the third, N is the name of the fourth orbit(shell). The electron holding capacity of each orbit is 2n2. [Where, n = 1,2 3,4. . .]

Now,

  • n = 1 for K orbit. The electron holding capacity of K orbit is 2n2 = 2 × 12 = 2 electrons.
  • For L orbit, n = 2. The electron holding capacity of the L orbit is 2n2 = 2 × 22 = 8 electrons.
  • n=3 for M orbit. The maximum electron holding capacity in M orbit is 2n2 = 2 × 32 = 18 electrons.
electron configuration
Electron Configuration

In addition to this method, electron configuration can be done through sub-orbits. The German physicist Aufbau first proposed an idea of electron configuration through sub-orbits. The Aufbau method is to do electron configuration through the sub-energy level.

These sub-orbitals are expressed by ‘l’. The Aufbau principle is that the electrons present in the atom will first complete the lowest energy orbital and then gradually continue to complete the higher energy orbital. These orbitals are named s, p, d, f. The electron holding capacity of these orbitals is s = 2, p = 6, d = 10 and f = 14.

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(Cl).

Step-1: Determining the total number of electrons

1st we need to know the total number of electrons in the chlorine(Cl) atom. To know the number of electrons, you need to know the number of protons in chlorine. And 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(Cl) elements from the periodic table. The atomic number is the number of protons. And electrons equal to protons are located outside the nucleus.

Position of chlorine(Cl) in the periodic table
Position of chlorine(Cl) in the periodic table

That is, we can finally say that there are electrons equal to the atomic number in the chlorine(Cl) atom. From the periodic table, we see that the atomic number of chlorine(Cl) is 17. That is, the chlorine(Cl) atom has a total of seventeen electrons.

Step-2: Need to do electron configuration

Step 2 is very important. In this step, the electrons of chlorine(Cl) have to be arranged. We know that chlorine atoms have a total of seventeen electrons. 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(orbit).

chlorine electron configuration
Chlorine electron configuration

That is, the first shell of chlorine has two electrons, the second shell has eight electrons and the 3rd shell(orbit) has seven electrons. The number of electrons per shell of chlorine(Cl) is 2, 8, 7. The electron configuration of chlorine through the sub-orbit is 1s2 2s2 2p6 3s2 3p5.

Step-3: Determining the valence shell(orbit) and calculate total electrons

The third step is to diagnose the valence shell(orbit). The last shell after the electron configuration is called the valence shell(orbit). The total number of electrons in a valence shell is called a valence electron.

The electron configuration of chlorine(Cl) shows that the last shell(orbit) of chlorine has seven( 3s2 3p5) electrons. Therefore, the valence electrons of chlorine(Cl) are seven. In this way, the valence electrons of all the elements can be determined.

Determination of the valency of chlorine(Cl)

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(valence) of that element.

The electron configuration of chlorine in excited state is Cl*(17) = 1s2 2s2 2p6 3s2 3px2 3py2 3pz1. The electron configuration of chlorine shows that there is one unpaired electron in the last orbit of chlorine.

valency and valence electrons of chlorine
Valency and valence electrons of chlorine(Cl)

Therefore, the valency(valence) of the 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 chlorine ion(Cl) have?

After arranging the electrons, it is seen that the last shell(orbit) of the chlorine(Cl) atom has seven electrons. In this case, the valence electrons of chlorine(Cl) are seven. We know the details about this.

The elements that have 5, 6, or seven electrons in the last shell(orbit) receive the electrons in the last shell(orbit) during bond formation. The elements that receive electrons and form bonds are called anions. That is, chlorine(Cl) is an anion element.

Cl + e → Cl

During the formation of chlorine(Cl) bonds, the last shell receives electrons and turns into a chlorine ion(Cl). The electron configuration of chlorine ion(Cl) is 1s2 2s2 2p6 3s2 3p6. The electron configuration of chlorine ions shows that chlorine ions have three shells(orbit) and the 3rd shell has eight electrons.

The electron configuration shows that the chlorine ion has acquired the electron configuration of argon. That is, in this case, the valence(valency) of chlorine ions is -1. Since the last shell of chlorine ion has eight electrons, the valence electrons of chlorine ion(Cl) are eight.

Compound formation of chlorine(Cl)

Chlorine(Cl) participates in the formation of bonds through its valence electron. We know that the valence electrons in chlorine(Cl) are seven. This valence electron participates in the formation of bonds with atoms of other elements.

sodium chloride structure and bonding
Sodium chloride structure and bonding

The electron configuration of sodium shows that the valence electron of sodium is one. The sodium atom donates its valence electron 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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