Protactinium – Periodic Table (Element Information & More)

Protactinium (Pa) element Periodic table

This is a SUPER easy guide on Protactinium element.

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

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

Let’s finish this very quickly.

Protactinium Element (Pa) Information

Appearance of ProtactiniumSilvery-white metallic luster
State of Protactinium at STPSolid
Position of Protactinium in Periodic tableProtactinium in periodic table (Position)
Group: actinides, Period: 7, Block: f
Category of Protactinium elementProtactinium element category
Inner transition metals
Atomic number of Protactinium, or 
Protons in Protactinium
91
Neutrons in Protactinium148
Electrons in Protactinium91
Symbol of ProtactiniumPa
Atomic mass of Protactinium Protactinium (Pa) atomic mass
231.04 u
Electrons arrangement in Protactinium

or 

Bohr model of Protactinium
Bohr model of protactinium (Electrons arrangement in protactinium, Pa)
2, 8, 18, 32, 20, 9, 2
Electronic configuration of Protactinium[Rn] 5f2 6d1 7s2
Atomic radius of ProtactiniumProtactinium (Pa) atomic radius
243 picometers (van der Waals radius)
1st Ionization energy of Protactinium5.89 eV
Electronegativity of Protactinium Electronegativity of Protactinium (Pa)
1.5 (Pauling scale)
Crystal structure of Protactiniumcrystal structure of protactinium
Tetragonal
Melting point of Protactinium1841 K or 1568 °C or 2854 °F
Boiling point of Protactinium4300 K or 4027 °C or 7280 °F
Density of Protactinium15.37 g/cm3
Main isotope of Protactinium231Pa
Who discovered Protactinium and when?Who discovered protactinium and when?
Kasimir Fajans (in 1913)
CAS number7440-13-3

See how this Interactive Periodic Table helps you

  • You can effortlessly find every single detail about the elements from this single Interactive Periodic table.
  • You will get the detailed information about the periodic table which will convert a newbie into pro.
  • You will also get the HD images of the Periodic table (for FREE).

Visit ➢ Periodic table

Protactinium in Periodic table

Protactinium element is in period 7 and in actinides group of the Periodic table. Protactinium is the f-block element and it belongs to inner transition metals group.

Click on above elements (in Periodic table) to see their information or Visit Interactive Periodic Table (which shows names, symbol, atomic mass, electron configuration, electrons arrangement, etc. of all the elements)

Click on above elements (in Periodic table) to see their information

←Move to: Thorium (Th) element – Periodic Table
→Move to: Uranium (U) element – Periodic Table

Why is Protactinium in Period 7?

Why is Protactinium in Period 7

Let me ask you a question.

How many shells does protactinium have?

It’s 7. Right?

You have already seen the bohr model of protactinium atom in the above table.

From the Bohr model, it can be found that the number of orbits or shells in protactinium is 7. Hence, as protactinium has 7 orbits, it lies in period 7 of the Periodic table. 

Why is Protactinium in f-block?

Why is Protactinium in f-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 protactinium is [Rn] 5f2 6d1 7s2.

So the last electron of protactinium enters the f-subshell or f-orbital. 

Hence, protactinium is the f-block element.

5 Interesting facts about Protactinium

Interesting facts about protactinium element are mentioned below.

  1. The name “Protactinium” was derived from the Greek word “protos” (which means first) and “actinium”.
  2. Protactinium element is present in very rare quantities in the earth’s crust and its concentration in earth’s crust is 0.1 parts per trillion only.
  3. Naturally occurring protactinium is obtained from uranium ores and its proportion in uranium ores is around 3 ppm.
  4. The largest amount of protactinium obtained till today is only 125 grams. This was extracted by the Great Britain Atomic Energy Authority from approximately 60 tonnes of nuclear waste. [1]
  5. Apart from being radioactive, it is also a toxic metal.

Properties of Protactinium

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

Physical properties of Protactinium

Physical properties of protactinium are mentioned below.

  • Protactinium is a dense metal having silvery-white metallic lustre.
  • Protactinium has around 29 isotopes and all of those isotopes are radioactive in nature.
  • The crystal structure of protactinium is tetragonal.
  • The atomic mass of protactinium is 231.04 u and its density is 15.37 g/cm3.
  • The melting point of protactinium is 1568 °C and its boiling point is 4027 °C.

Chemical properties of Protactinium

Chemical properties of protactinium are mentioned below.

  • Protactinium is a radioactive element and dangerous to humans as well as animals.
  • In compound forms, the most common oxidation state of protactinium is +5. But apart from this, it also exists in other oxidation states like +2, +3 and +4.
  • Protactinium reacts with water vapor, oxygen as well as acids, but it does not react with alkalis.

Uses of Protactinium

Protactinium is generally used for research work in chemistry. Protactinium has no commercial  uses due to its radioactive nature and scarcity.

Free Gift for you: Interactive Periodic Table

Let me tell you how this Interactive Periodic Table will help you in your studies.


1).
You can effortlessly find every single detail about the elements from this single Interactive Periodic table.

(For Interactive Periodic table, view on laptop/desktop for better experience. If you are on mobile device, then use a “Desktop site mode” to see interactive periodic table)

2). You will get the detailed information about the periodic table which will convert a newbie into pro.

3). You will also get the HD images of the Periodic table (for FREE).

Checkout Interactive Periodic table and download it’s high resolution image now (It’s FREE)

References:
Chemical data: Wikipedia, Chemspider
Kasimir Fajans: Image by NN (University of Michigan), Public domain, via Wikimedia Commons

Leave a Comment