Protactinium – Periodic Table [Element Information & More]

Protactinium element (Pa) is in period 7 of a periodic table. Protactinium is in the f-block and it is classified as an actinide on the periodic table.

There is a lot more information related to protactinium which is mentioned in the Information Table given below.

So let’s dive right into it!

Table of contents

• Protactinium element (Information Table)
• Protactinium element in Periodic table
• Facts about Protactinium
• Properties of Protactinium
• Uses of Protactinium

Protactinium Element (Information Table)

The important data related to protactinium element is given in the table below.

Appearance of protactinium	Silvery white metallic appearance
Atomic number of protactinium	91
Symbol of protactinium	Pa
Atomic mass of protactinium	231.04 u
Protons, Neutrons & Electrons in protactinium	Protons: 91, Neutrons: 148, Electrons: 91
State of protactinium (at STP)	Solid
Period number of protactinium in periodic table	7
Block of protactinium in periodic table	f-block
Category of protactinium	Inner transition metals
Bohr model or Electrons per shell or Electrons arrangement in protactinium	2, 8, 18, 32, 20, 9, 2
Electron configuration of protactinium	[Rn] 5f2 6d1 7s2
Orbital diagram of protactinium
Electronegativity of protactinium (on pauling scale)	1.5
Atomic radius of protactinium (van der Waals radius)	243 picometers
Density of protactinium	15.37 g/cm3
1st ionization energy of protactinium	5.89 eV
Main isotope of protactinium	231Pa
Melting point of protactinium	1841 K or 1568 °C or 2854 °F
Boiling point of protactinium	4300 K or 4027 °C or 7280 °F
Crystal structure of protactinium	Tetragonal
Discovery of protactinium	By Kasimir Fajans in 1913

Also see: Interactive Periodic Table (It has rotating bohr models as well as many other details of all the 118 elements in a single periodic table).

Protactinium element in Periodic table

The Protactinium element (Pa) has the atomic number 91 and is located in period 7. Protactinium is a metal and it is classified as an actinide group element.

Click on above elements in the periodic table to see their information.

Facts about protactinium

Here are a few interesting facts about the protactinium element.

1. Protactinium was given its name from the Greek word “protos” (meaning first) and “actinium”.
2. The concentration of protactinium in the earth’s crust is around 0.1 parts per trillion (which is very very less).
3. Protactinium is naturally obtained from uranium ores and these uranium ores contain protactinium in the concentration of 3 ppm.
4. Protactinium is a radioactive as well as toxic metal.

Properties of protactinium

Here is a list of some physical properties and chemical properties of protactinium.

Physical properties of protactinium

• Protactinium has a silvery white appearance.
• Protactinium has tetragonal crystal structure.
• The melting point and boiling point of protactinium is 1841 K and 4300 K respectively.
• There are around 29 isotopes of protactinium and all these isotopes are radioactive in nature.
• The density of protactinium is 15.37 g/cm³ and its atomic mass is 231.04 amu.

Chemical properties of protactinium

• Protactinium is a toxic as well as radioactive element.
• There are different oxidation states of protactinium, but the most common oxidation state is +5.
• Protactinium does not show any reaction with alkalis, but it reacts with moisture, oxygen as well as acids.

Uses of protactinium

Protactinium is not used commercially because of its scarcity and radioactivity. It is generally used for research work.

External resources:

1. Protactinium – Element information, properties and uses | Periodic Table. (n.d.). Protactinium – Element Information, Properties and Uses | Periodic Table. https://www.rsc.org/periodic-table/element/91/protactinium
2. Prohaska, T., et al. (2022, May 1). Standard atomic weights of the elements 2021 (IUPAC Technical Report). Pure and Applied Chemistry, 94(5), 573–600. https://doi.org/10.1515/pac-2019-0603
3. Haynes, W. M. (Ed.). (2014, June 4). CRC Handbook of Chemistry and Physics. https://doi.org/10.1201/b17118
4. Kaye, G W.C., & Laby, T H. Tables of physical and chemical constants. 15th Edition. United States.
5. Sansonetti, J. E., & Martin, W. C. (2005, December). Handbook of Basic Atomic Spectroscopic Data. Journal of Physical and Chemical Reference Data, 34(4), 1559–2259. https://doi.org/10.1063/1.1800011
6. Protactinium – Wikipedia. (2019, January 9). Protactinium – Wikipedia. https://en.wikipedia.org/wiki/Protactinium
7. P. (n.d.). Protactinium | Pa (Element) – PubChem. Protactinium | Pa (Element) – PubChem. https://pubchem.ncbi.nlm.nih.gov/element/Protactinium
8. It’s Elemental – The Element Protactinium. (n.d.). It’s Elemental – the Element Protactinium. https://education.jlab.org/itselemental/ele091.html
9. Bondi, A. (1964, March). van der Waals Volumes and Radii. The Journal of Physical Chemistry, 68(3), 441–451. https://doi.org/10.1021/j100785a001
10. Holden, et al. (2018, December 1). IUPAC Periodic Table of the Elements and Isotopes (IPTEI) for the Education Community (IUPAC Technical Report). Pure and Applied Chemistry, 90(12), 1833–2092. https://doi.org/10.1515/pac-2015-0703
11. Zhang, et al. (2011, January 11). Corrected Values for Boiling Points and Enthalpies of Vaporization of Elements in Handbooks. Journal of Chemical & Engineering Data, 56(2), 328–337. https://doi.org/10.1021/je1011086
12. Scerri, E. (2013, July 18). Element 91—Protactinium. A Tale of Seven Elements. https://doi.org/10.1093/oso/9780195391312.003.0008
13. C&EN: IT’S ELEMENTAL: THE PERIODIC TABLE – PROTACTINIUM. (n.d.). C&EN: IT’S ELEMENTAL: THE PERIODIC TABLE – PROTACTINIUM. https://pubsapp.acs.org/cen/80th/protactinium.html?