Phosphorus (P) – Periodic Table (Element Information & More)

This is a SUPER easy guide on Phosphorus element.

In fact, the table mentioned below is the perfect information box (Which gives you every single detail about the Phosphorus element in Periodic table.)

So if you want to know anything about the Phosphorus element, then this guide is for you.

Let’s dive right into it!

Phosphorus Element (P) Information

Appearance	Waxy white or yellow, Red, Violet, Metallic color
State (at STP)	Solid
Position in Periodic table	Group: 15, Period: 3, Block: p
Category	Pnictogens
Atomic number or  Protons	15
Neutrons	16
Electrons	15
Symbol	P
Atomic mass	30.974 u
Electrons arrangement or  Bohr model	2, 8, 5
Electronic configuration	[Ne] 3s2 3p3
Atomic radius	180 picometers (van der Waals radius)
Valence electrons	5
1st Ionization energy	10.487 eV
Electronegativity	2.19 (Pauling scale)
Crystal structure	Orthorhombic
Melting point of Phosphorus (white)	317.3 K or 44.15 °C or 111.5 °F
Boiling point of Phosphorus (white)	553.7 K or 280.5 °C or 536.9 °F
Density	1.823 g/cm3
Main isotope	31P
Who discovered Phosphorus and when?	Hennig Brand in 1669
CAS number	12185-10-3 (white phosphorus) 7723-14-0 (red phosphorus)

Phosphorus in Periodic table

Phosphorus element is in group 15 and period 3 of the Periodic table. Phosphorus is the p-block element and it belongs to Pnictogens group.

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Why is Phosphorus in Group 15?

Do you know, how many electrons can be accommodated in the first shell, second shell, third shell, fourth shell, etc…?

Here is the table showing the capacity of orbits to hold electrons. 

Number of electrons in shells.

Orbit / Shell (n)	Maximum no. of electrons this orbit can hold
K shell, n = 1	2 × 1² = 2
L shell, n = 2	2 × 2² = 8
M shell, n = 3	2 × 3² = 18
N shell, n = 4	2 × 4² = 32

Thus, 

• 1st shell can hold 2 electrons.
• 2nd shell can hold 8 electrons.
• 3rd shell can hold 18 electrons.
• 4th shell can hold 32 electrons.

Now the atomic number of phosphorus (P) is 15.

Hence the phosphorus element has electrons arrangement 2, 8, 5.

This electron arrangement indicates that the outermost orbit of phosphorus element (P) has 5 electrons.

Hence, it lies in group 15.

Why is Phosphorus in Period 3?

Let me ask you a question.

How many shells does phosphorus have?

It’s 3. Right? 

You have already seen the bohr model of phosphorus element in the above table.

From the Bohr model, it can be found that the number of orbits or shells in phosphorus is 3. Hence, as phosphorus has 3 orbits, it lies in period 3 of the Periodic table. 

Why is Phosphorus in p-block?

Before knowing this reason, first of all I want to ask you a simple question.

How can you determine the blocks-wise position of elements?

The simple answer: The elements will lie in the s, p, d or f block will completely depend upon the subshell in which the last electron will enter.

For example; the electron configuration of phosphorus is [Ne] 3s² 3p³. 

So the last electron of phosphorus enters the p-subshell or p-orbital. 

Hence, phosphorus is the p-block element.

7 Interesting facts about Phosphorus

Interesting facts about phosphorus element are mentioned below.

1. According to the study in 2013, meteorites may have brought phosphorus on the earth.
2. Average human body contains around 750 grams of phosphorus. [1]. In the human body, phosphorus is present in bones as well as DNA and RNA.
3. Pure phosphorus is harmful for the human body.
4. White phosphorus when comes in contact with the body, it causes chemical burns.
5. The amount of phosphorus is abundant in the earth’s crust and it is about 1050 ppm by weight.
6. Phosphorus is the 11th most abundant element in the earth crust.
7. The first striking matchstick was made of white phosphorus combined with other elements, but nowadays matchsticks are made of phosphorus sesquisulfide (whose chemical formula is P₄ S₃).

Properties of Phosphorus

The physical and chemical properties of phosphorus element are mentioned below.

Physical properties of Phosphorus

Physical properties of phosphorus are mentioned below.

• Phosphorus is a waxy white in color. Apart from this the phosphorus is also found in yellow, red, and metallic colors.
• White phosphorus slightly glows in the air.
• Phosphorus is a nonmetal and it is a bad conductor of heat and electricity.
• The melting point of white phosphorus is 44.15 °C and its boiling point is 280.5 °C.
• The metallic colored phosphorus has an ability to conduct electricity.

Chemical properties of Phosphorus

Chemical properties of phosphorus are mentioned below.

• Phosphorus is a chemically reactive element and it is not found in a free state, but is always found as a compound with other elements.
• Phosphorus has many isotopes, but out of them only one is stable (i.e ³¹P) and has an abundance of 100%.
• When phosphorus is heated with metals it forms phosphides.
• Phosphorus element can easily combine with halogens.
• White phosphorus is very reactive to oxygen and so it is kept inside water in labs.

Uses of Phosphorus

Uses of phosphorus are mentioned below.

• Red phosphorus is used on the side of a matchstick box for igniting the matchstick.
• Phosphorus is mainly used in preparation of fertilizers for plants.
• Phosphorus is also used in making of flares, LEDs, matchsticks as well as it is used in production of steel.
• Phosphorus containing compound, Sodium triphosphate is used in making detergents and food preservatives.
• Dicalcium phosphate is used in toothpaste which acts as a polishing agent.

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External resources:

1. Phosphorus – American Chemical Society. (n.d.). American Chemical Society. https:///greenchemistry/research-innovation/endangered-elements/phosphorus.html
2. Krafft, F. (1969, September). Phosphorus. From Elemental Light to Chemical Element. Angewandte Chemie International Edition in English, 8(9), 660–671. https://doi.org/10.1002/anie.196906601
3. Phosphorus – Element information, properties and uses | Periodic Table. (n.d.). Phosphorus – Element Information, Properties and Uses | Periodic Table. https://www.rsc.org/periodic-table/element/15/phosphorus
4. Phosphorus – Wikipedia. (2011, November 19). Phosphorus – Wikipedia. https://en.wikipedia.org/wiki/Phosphorus