How many valence electrons does Phosphorus have?

What is the valency of phosphorus(P) Valence electrons

Phosphorus is the fifteenth element in the periodic table. Phosphorus is the element in group 15. Its symbol is “P”. Through its valence electrons, phosphate forms bonds. This article explains in detail the valence electrons for phosphorus (P). There are two main forms of elemental phosphorus: white and red. However, it is highly reactive so phosphorus cannot be found free on Earth. It is found in Earth’s crust at a level of approximately one gram per kilogram (compare with copper, which is about 0.06 grams). Phosphore is the most common form of phosphorus in minerals.


Phosphorus element


The 12th-century Arabian alchemists may have accidentally isolated elemental Phosphorus, but records are not clear. Hennig Brand was a German merchant who discovered phosphorus in 1669. His hobby was alchemy. 50 buckets of urine were left to ferment until Brand, a German a merchant, allowed them to remain. He then heated the paste with sand to extract elemental phosphorus. In a letter to Gottfried Wilfried Leibniz Brand reported his discovery. Afterwards, public interest was piqued by demonstrations of the element’s ability to glow in darkness, or “phosphoresce”, and subsequent letters. Phosphorus was a chemical curiosity for a century until it was discovered to be part of bone.


White phosphorus can be used in flares or incendiary devices. Red phosphorus can be found in matchboxes stuck to the sides. This material is used to strike safety matches to prevent them from being lit. Fertilizers are the most common use of phosphorus compounds. Phosphate ores are the basis of ammonium phosphate. Before being converted to ammonium, phosphate is made from the ores.

The production of steel also depends on phosphate. Although phosphates are an ingredient in detergents, they are slowly being phased out of some countries. They can cause high levels of phosphate in water supplies, which can lead to unwanted growth. Also, phosphates are used in the manufacture of fine chinaware and special glasses.

Health effects of phosphorus

Most commonly, phosphates are the source of phosphorus in the environment. Because phosphates are an important part of DNA and energy distribution, phosphotes are essential substances in the human body. Also, phosphates are common in plants.

The natural phosphate supply has been altered dramatically by humans using phosphate rich manures and phosphate-containing detergents. A variety of foodstuffs such as cheese, sausages, and hams were also treated with phosphates.

Phosphate should be a part of your daily diet. The recommended intake is 800mg/day. A normal diet will provide between 1000mg and 2000mg/day depending on how many phosphate-rich foods are consumed.

Position of Phosphorus in the periodic table

Position of Phosphorus in the periodic table

Allotropes of Phosphorus

White Phosphorus

White phosphorus, the most dangerous allotrope of this element, is white phosphorus. It is a translucent, waxy substance that glows in the dark. White phosphorus can spontaneously ignite when exposed to air. Contact with skin can cause severe burns. White phosphorus can burn and form phosphorus pentoxide.

White phosphorus can be extremely dangerous and cause serious harm or even death. When exposed to heat and light, it slowly becomes red phosphorus. This is why white phosphorus often appears yellow.

Four phosphorus atoms are connected to each other in closed rings by covalent bonds in white phosphorus molecules. This configuration creates strain in the molecule and explains its highly reactive properties.

Violet Phosphorus

Violet phosphorus is the most reactive of allotropes. It reacts slowly to halogens. It appears almost all-black but slightly purple crystalline solid.

The heating of red phosphorus or the dissolution of white phosphorus by molten lead can create violet phosphorus. Scientists continue to study its lattice structure with x-ray difffraction methods.

Black Phosphorus

Red phosphorus has a higher level of reactiveness than black phosphorus. Black phosphorus appears as a black, lustrous and crystalline solid. These molecules are made up of crystal lattices, which form by the linking of existing P-P–P bonds.

Black phosphorus comes in two forms: a-black and b-black. The heating of redphosphorus results in the formation of the more stable form. The latter, which is more reactive, can be synthesized by heating white phosphorus under high pressure.

This configuration gives black phosphorus a greater degree of stability due to the higher bond angle. Black phosphorus is a less reactive allotrope than sulfur, oxygen, and halogens.

Red Phosphorus

This allotrope is more toxic than its counterpart. It appears as a powdery, red-ironed, lustrous substance. Red phosphorus has a higher stability and is less dangerous than white. You can extract it from small amounts of striker strips on match boxes.

Red phosphorus is formed when white phosphorus rings are polymerized via covalent bonds to create straight chains. These chains reduce intramolecular strain and decrease reactivity.

atomic number15
atomic weight30.9738
boiling point (white)280 °C (536 °F)
melting point (white)44.1 °C (111.4 °F)
density (white)1.82 gram/cm3 at 20 °C (68 °F)
oxidation states−3, +3, +5
electron configuration1s22s22p63s23p3

Natural abundance

Although phosphate is often found in complex mixtures in nature, it is also common to find it in mineral compounds. Phosphorus is also found in large quantities in the USA, including phosphate rocks. It is possible that we will see a peak in phosphorus around 2050.

In an industrial furnace, white phosphorus can be heated in phosphate rock with the addition of silica and carbon. This creates phosphorus vapour which is then collected under water. In the absence of air, red phosphorus can be made by heating white phosphorus gently to 250°C.

Biological role

All living things require phosphate. It is the backbone of DNA, RNA’s sugar-phosphate structure. It is essential for energy transfer in cells, as part of ATP (adenosine Triphosphate). It can also be found in many biologically important molecules. Since our bones and teeth are mostly calcium phosphate, we consume about 1 gram per day. We also store approximately 750 grams of it in our bodies. The over-use of fertilizers and detergents can lead to a rapid growth of algae and polluting rivers and lakes. Algae block light, preventing further photosynthesis. The lake soon dies from the excess oxygen in its water.

What are the valence electrons for phosphorus (P)?

P is the second element in group-15. The total number of electrons in a last orbit is called the valence electron. The valence electrons (P) are the total number of electrons remaining in the shell after the electron configuration is complete. The properties and formation of bonds are controlled by the valence electrons. P is the fifteenth element on the periodic table.

What are the valence electrons for phosphorus (P)

What number of electrons, protons, and neutrons does P (phosphorus) possess?

The nucleus can be found in the middle of an atom. The nucleus is home to protons and neutrons. 15. The number of protons in a phosphorus atom is called the atomic number. The number of protons found in phosphorus is fifteen. The nucleus contains a circular shell containing electrons that are equal to protons. The phosphorus atom is composed of 15 electrons.

The difference between the number atomic masses and the number atoms is what determines the number neutrons within an element. This means that neutron number (n) = atomic mass (A) + atomic number (Z).

We know that the atomic quantity of phosphorus (n) is 15, and that its atomic mass is 31 (30.97376200u). Neutron (n) = 31 – 15 = 16. The number of neutrons found in phosphorus (P) is therefore 16.

Valence is the ability of an atom of a chemical element to form a certain number of chemical bonds with other atoms. It takes values from 1 to 8 and cannot be equal to 0. It is determined by the number of electrons of an atom spent to form chemical bonds with another atom. The valence is a real value. Numerical values of valence are indicated with roman numerals (I,II, III, IV, V, VI, VII, VIII).

How can you find the number of valence neutrons in a phosphorus (P) atom?

Following a few steps, you can determine the valence electrons. One of these is the electron configuration. Without an electron configuration, it is impossible to determine the valence of an electron. It is easy to find the value electrons for all elements by knowing the electron configuration. This site has an article that explains the electron configuration. You can find it here. This article focuses on electron configuration.

However, it is possible to identify valence electrons by placing electrons according the Bohr principle. We will now learn how to identify the valence electron for phosphorus (P).

Calculating the number of electrons in phosphorus (P)

1st we need to know the total number of electrons in the Phosphorus (P) atom. You need to know how many protons are in phosphorus to determine the number electrons. To know the number protons, you must know the atomic number for the phosphorus element.

A periodic table is required to determine the atomic number. The periodic table contains the atomic number for phosphorus (P) elements. The number of protons is called the atomic number. The nucleus also contains electrons that are equal to protons. This means that electrons are equal to the number of protons in the phosphorus-atom atom. The atomic number for phosphorus is 15 according to the periodic table. This means that a phosphorus atom contains a total number of fifteen electrons.

The terms “oxidation degree” and “valence” may not be the same, but they are numerically almost identical. The conditional charge of an atom’s atom is called the oxidation state. It can be either positive or negative. Valence refers to the ability of an atom form bonds. It cannot have a negative value.

You will need to perform electron configuration of the phosphorus (P)

Important step 2. This step involves the arrangement of electrons for phosphorus (P). The phosphorus atom contains a total number of fifteen electrons. The electron configuration of phosphorus shows there are two electrons within the K shell, eight inside the L shell and five in M shell(orbit). The first shell of phosphorus (P) has two electrons while the second shell has eight and the third shell has five electrons. There are 2, 8 electrons in each shell of phosphorus. The electron configuration for phosphorus in the sub-orbit is 1s2 2s2 2p6 3s2 3p3. This site has an article that explains the electron configuration for phosphorus(P). You can read it if interested.

Calculate the total electrons and determine the valence shell

The third step is to determine the orbit of the valence shell. The valence shell is the last shell after the electron configuration. A valence electron is the total number of electrons found in a valenceshell. The electron configuration for phosphorus indicates that the last shell has five electrons. The valence electrons for phosphorus (P) have five.

  1.  The valence is a numerical characteristic of the ability of atoms of a given element to bond with other atoms.
  2. The valence of hydrogen is constant and equal to one.
  3. The valence of oxygen is also constant and equal to two.
  4. The valence of most of the other elements is not constant. It can be determined by the formulas of their binary compounds with hydrogen or oxygen.

Phosphorus compound formation (P)

Through its valence electrons, phosphate(P) is involved in the formation bonds. This valence electron is involved in the formation bonds with other elements’ atoms. By sharing electrons with other elements, phosphate atoms create bonds. The electron configuration for chlorine indicates that there are seven value electrons in chlorine. By sharing electrons, three chlorine atoms make phosphorus trichloride (PCl 3) compounds.

Compound formation of phosphorus(P)

The phosphorus (P) atom thus completes its octave, and gains the electron configuration of Argon. The electron configuration of argon is also acquired by chlorine.

Compound formation of phosphorus(P) (balanced)

One phosphorus element shares electrons with three atoms of chlorine to form the compound phosphorus trichloride (PCl 3). This is done by forming a covalent bond. Phosphorus trichloride(PCl3) is covalent bonding.

What number of valence electrons does the phosphorus ion (P 3) possess?

During bond formation, elements with 5, 6, or 7 electrons in their last shells receive electrons from the shells that contain them. Anions are elements that have electrons and can form bonds. Phosphorus(P) is an example of an anion element. The last shell of phosphorus receives electrons during the formation of a bond and transforms them into phosphorus (P3).

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

ion(P3-) electron configuration is 1s2 2s2 2p6 3s2 3p6. The electron configuration for phosphorus shows that the ion has three shells, while the third shell contains eight electrons. This electron configuration shows the phosphorus has the electron arrangement of argon. In this instance, the valence for phosphorus ions (P 3) was -3. The valence electrons for phosphorus (P 3) have eight electrons since the shell that contains the last phosphorus ison has eight.

What is the valency for phosphorus (P)?

Valency (or valence) is the ability of an element’s atom to join another atom in the formation of a molecule. The valency is the number of unpaired electrons found in an element’s last orbit. Ground state electron configuration for phosphorus is 1s2 2s2 2p6 3s1 3px1 3py1 3pz1 3dxy1. This electron configuration shows three unpaired electrons are present in the last orbit for phosphorus. The valency of the Phosphorus atom is therefore 3.

The electron configuration of an element in its excited state determines its value. In the excited state, Phosphorus(P*)  electron configuration will be 1s2 2s2 2p6 3s1 3px1 3py1 3pz1 3dxy1. This electron configuration shows us that the last shell containing a phosphorus atom contains five unpaired electrons. The bond formation determines the valency of phosphorus.

What is the valency of phosphorus(P)

The valency for phosphorus is therefore 5.

Phosphorus Facts:

  • The seventh most frequent element is phosphorus.
  • Hennig Brand isolated the phosphorus from his urine. Instead of keeping his secret, he decided to make the process available to other alchemists. The French Academy of Sciences sold his process, making it more well-known.
  • Green glow is produced by the oxidation in air of white phosphorus. While “phosphorescence” is used to describe the element’s glow it actually refers only to its oxidation. Chemiluminescence is the glow of phosphorus.
  • The sixth most common element in the human body is phosphorus.
  • Phosphorus, the eighteenth most abundant element in seawater, is also known as phosphorus.
  • Carl Wilhelm Scheele’s method for extracting phosphorus bones from bones replaced Brand’s.
  • White phosphorus was used in early matches. When workers were over-exposed, this practice led to the painful and debilitating deformation in the jawbone called ‘phossy’.


  • Mary Elvira Weeks, The discovery of the elements. II. Elements known to the alchemists J. Chem. Educ., 1932.
  • Mary Elvira Weeks, The discovery of the elements. XXI. Supplementary note on the discovery of phosphorus J. Chem. Educ., 1933.
  • Egon Wiberg; Nils Wiberg; Arnold Frederick Holleman (2001). Inorganic chemistry. Academic Press.
  • Ellis, Bobby D.; MacDonald, Charles L. B. (2006). “Phosphorus(I) Iodide: A Versatile Metathesis Reagent for the Synthesis of Low Oxidation State Phosphorus Compounds”. Inorganic Chemistry.
  • Wang, Yuzhong; Xie, Yaoming; Wei, Pingrong; King, R. Bruce; Schaefer, Iii; Schleyer, Paul v. R.; Robinson, Gregory H. (2008). “Carbene-Stabilized Diphosphorus”. Journal of the American Chemical Society.
Alexander Stephenson

Candidate of Chemical Sciences, editor-in-chief of Lecturer at several international online schools, member of the jury of chemistry competitions and author of scientific articles.

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