# How many valence electrons does phosphorus(P) have?

The fifteenth element of the periodic table is phosphorus. The element of group-15 is phosphorus and, its symbol is ‘P’. Phosphorus forms bonds through its valence electrons. This article discusses in detail the valence electrons of phosphorus(P).

## How many electrons and protons does phosphorus(P) atom have?

The nucleus is located in the center of the atom. Protons and neutrons are located in the nucleus. The atomic number of phosphorus(P) is 15. The atomic number is the number of protons.

That is, the number of protons in the phosphorus(P) is fifteen. Electrons equal to protons are located in a circular shell outside the nucleus. That is, phosphorus(P) atoms have a total of fifteen electrons.

## What are the valence electrons of phosphorus(P)?

The second element in group-15 is phosphorus(P). The valence electron is the total number of electrons in the last orbit. The total number of electrons in the last shell after the electron configuration of phosphorus is called the valence electrons of phosphorus(P).

The valence electrons determine the properties of the element and participate in the formation of bonds. The fifteenth element in the periodic table is phosphorus(P).

That is, the atom of the phosphorus element has a total of fifteen electrons. The electron configuration of the phosphorus shows that the last shell(orbit) of phosphorus(P) has a total of five electrons.

That is, we can easily say that the valence electrons of phosphorus(P) are five. There is an article on this site detailing the electron configuration of phosphorus(P), you can read it if you want.

## How to determine the valence electron of phosphorus(P)?

Now we will know how to easily determine the valence electrons of phosphorus(P). 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(shell). 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 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.

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 phosphorus(P).

Step 1 – 1st we need to know the total number of electrons in the phosphorus(P) atom. To know the number of electrons, you need to know the number of protons in phosphorus. And to know the number of protons, you need to know the atomic number of the phosphorus 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 phosphorus(P) 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 phosphorus atom. From the periodic table, we see that the atomic number of phosphorus(P) is 15. That is, a phosphorus(P) atom has a total of fifteen electrons.

Step 2 – Step-2 is very important. In this step, the electrons of phosphorus(P) have to be arranged. We know that the phosphorus atom has a total of fifteen electrons. The electron configuration of the phosphorus shows that there are two electrons in the K shell, eight in the L shell, and five in the M shell(orbit).

That is, the first shell of phosphorus(P) has two electrons, the second shell has eight electrons and the 3rd shell(orbit) has five electrons. The number of electrons per shell of phosphorus is 2, 8, 5. The electron configuration of phosphorus(P) through the sub-orbit is 1s2 2s2 2p6 3s2 3p3.

Step 3 – 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 phosphorus shows that the last shell of phosphorus has five electrons. Therefore, the valence electrons of phosphorus(P) are five. In this way, the valence electrons of all the elements can be determined.

## Determination of the valency of phosphorus(P)

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.

As we know, the electron configuration of a phosphorus atom is normally 1s2 2s2 2p6 3s2 3p3. In the electron configuration for phosphorus(P), we see that 5 electrons exist in the last orbit of the phosphorus. Therefore, the valency(valence) of phosphorus(P) are 5.

Again, Valence is determined from the electron configuration of the element in the excited state. The electron configuration of phosphorus(P) in excited state is P*(15) = 1s2 2s2 2p6 3s2 3px1 3py1 3pz1.

Here, the electron configuration shows that three unpaired electrons exist in the last orbit of phosphorus. In this case, the valency(valence) of the phosphorus atom is 3. The valence(valency) of phosphorus is determined depending on the bond formation.

## How many valence electrons does phosphorus ion(P3-) have?

After arranging the electrons, it is seen that the last shell of the phosphorus(P) atom has five electrons. In this case, the valence electrons of phosphorus are 5. 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 during bond formation. The elements that receive electrons and form bonds are called anions. That is, phosphorus(P) is an anion element.

P + 3e → P3-

During the formation of bond, the last shell receives electrons and turns them into phosphorus ions(P3-). The electron configuration of phosphorus ion(P3-) is 1s2 2s2 2p6 3s2 3p6.

The electron configuration of phosphorus ions shows that phosphorus ions have three shells and the 3rd shell has eight electrons. The electron configuration shows that the phosphorus ion has acquired the electron configuration of argon.

That is, in this case, the valence of phosphorus ions(P3-) is -3. Since the last shell(orbit) of a phosphorus ion has 8 electrons, the valence electrons of phosphorus ion(P3-) are eight.

## Compound formation of phosphorus(P)

Phosphorus(P) participates in the formation of bonds through its valence electrons. We know that the valence electrons in phosphorus are five. This valence electron participates in the formation of bonds with atoms of other elements. Phosphorus atoms form bonds by sharing electrons with chlorine atoms.

The electron configuration of chlorine shows that the valence electrons of chlorine are seven. Three chlorine atoms and one phosphorus atom make phosphorus trichloride(PCl3) compounds by sharing electrons.

P + Cl2 → PCl3

As a result, the phosphorus(P) atom completes its octave and acquires the electron configuration of argon. On the other hand, chlorine also acquires the electron configuration of argon.

P4 + 6 Cl2 → 4 PCl3 (balanced)

Therefore, one phosphorus atom shares electrons with three chlorine atoms to form the phosphorus trichloride(PCl3) compound through a covalent bond. Phosphorus trichloride(PCl3) is covalent bonding.